Added docs for bundle task to readme (#211)

* Added docs for bundle task to readme

* Added notes about using secure files for keeping json auth file

* Fixed links format

baseREADME.md

@@ -96,7 +96,7 @@ Allows you to release an update to your app on Google Play, and includes the fol
     ![Service Endpoint](images/auth-with-endpoint.png)
 
     Note that in order to use the JSON Auth File method, the JSON file you get from the developer console needs to be checked into your source repo.
-
+    Please also note that from the point of security it's preferrable to store it as [Secure file](https://docs.microsoft.com/azure/devops/pipelines/library/secure-files) and download using [Download Secure File task](https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/download-secure-file).
 
 2. **APK Path** *(File path, Required)* - Path to the APK file you want to publish to the specified track.
 
@@ -166,7 +166,7 @@ Allows you to promote a previously released APK from one track to another (e.g.
 
 ![Promote task](images/promote-task.png)
 
-1. **JSON Key Path** *(File path)* or **Service Endpoint** - The credentials used to authenticate with Google Play. This can be acquired from the [Google Developer API console](https://console.developers.google.com/apis) and provided either directly to the task (via the `JSON Auth File` authentication method), or configured within a service endpoint that you reference from the task (via the `Service Endpoint` authentication method). Note that in order to use the JSON Auth File method, the JSON file you get from the developer console needs to be checked into your source repo.
+1. **JSON Key Path** *(File path)* or **Service Endpoint** - The credentials used to authenticate with Google Play. This can be acquired from the [Google Developer API console](https://console.developers.google.com/apis) and provided either directly to the task (via the `JSON Auth File` authentication method), or configured within a service endpoint that you reference from the task (via the `Service Endpoint` authentication method). Note that in order to use the JSON Auth File method, the JSON file you get from the developer console needs to be checked into your source repo. Please note that from the point of security it's preferrable to store it as [Secure file](https://docs.microsoft.com/azure/devops/pipelines/library/secure-files) and download using [Download Secure File task](https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/download-secure-file).
 
 2. **Package Name** *(String, Required)* - The unique package identifier (e.g. `com.foo.myapp`) that you wish to promote.
 
@@ -182,7 +182,7 @@ Allows you to increase the rollout percentage of an app that was previously rele
 
 ![Increase task](images/increase-task.png)
 
-1. **JSON Key Path** *(File path)* or **Service Endpoint** - The credentials used to authenticate with Google Play. This can be acquired from the [Google Developer API console](https://console.developers.google.com/apis) and provided either directly to the task (via the `JSON Auth File` authentication method), or configured within a service endpoint that you reference from the task (via the `Service Endpoint` authentication method). Note that in order to use the JSON Auth File method, the JSON file you get from the developer console needs to be checked into your source repo.
+1. **JSON Key Path** *(File path)* or **Service Endpoint** - The credentials used to authenticate with Google Play. This can be acquired from the [Google Developer API console](https://console.developers.google.com/apis) and provided either directly to the task (via the `JSON Auth File` authentication method), or configured within a service endpoint that you reference from the task (via the `Service Endpoint` authentication method). Note that in order to use the JSON Auth File method, the JSON file you get from the developer console needs to be checked into your source repo. Please note that from the point of security it's preferrable to store it as [Secure file](https://docs.microsoft.com/azure/devops/pipelines/library/secure-files) and download using [Download Secure File task](https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/download-secure-file).
 
 2. **Package Name** *(String, Required)* - The unique package identifier (e.g. com.foo.myapp) of the app you wish to increase the rollout percentage for.
 
@@ -191,3 +191,55 @@ Allows you to increase the rollout percentage of an app that was previously rele
 ## Contact Us
 
 * [Report an issue](https://github.com/Microsoft/google-play-vsts-extension/issues)
+
+### Google Play - Release Bundle
+
+Allows you to release an app bundle to Google Play, and includes the following options:
+
+1. **JSON Key Path** *(File path)* or **Service Endpoint** - The credentials used to authenticate with Google Play. This can be acquired from the [Google Developer API console](https://console.developers.google.com/apis) and provided either directly to the task (via the `JSON Auth File` authentication method), 
+
+    ![JSON Auth File](images/auth-with-json-file.png)
+
+    or configured within a service endpoint that you reference from the task (via the `Service Endpoint` authentication method). 
+
+    ![Service Endpoint](images/auth-with-endpoint.png)
+
+    Note that in order to use the JSON Auth File method, the JSON file you get from the developer console needs to be checked into your source repo.
+    Please note that from the point of security it's preferrable to store it as [Secure file](https://docs.microsoft.com/azure/devops/pipelines/library/secure-files) and download using [Download Secure File task](https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/download-secure-file).
+
+
+2. **Application id** *(String, Required)* - The application id of the bundle you want to release, e.g. com.company.MyApp.
+
+    ![Application id](images/bundle-app-id.png)
+
+3. **Bundle path** *(File path, Required)* - Path to the bundle (.aab) file you want to publish to the specified track. Wildcards can be used. For example, **/*.aab to match the first APK file, in any directory.
+
+4. **Track** *(String, Required)* - Track you want to publish the bundle to.
+
+5. **Roll out release** *(Boolean, Optional)* - Roll out the release to a percentage of users.
+
+6. **Update metadata** *(Boolean, Optional)* - An IETF language tag identifying the language of the release notes as specified in the BCP-47 document. Default value is _en-US_.
+
+7. **Release notes (file)** *(File path, Required if visible)* - Path to the file specifying the release notes (change log) for the APK you are publishing.
+
+    ![Release Notes](images/bundle-release-notes.png)
+
+8. **Language code** *(String, Required if visible)* - An IETF language tag identifying the language of the release notes as specified in the BCP-47 document. Default value is _en-US_.
+
+9. **Deobfuscation path** *(String, Optional)* - The path to the proguard mapping.txt file to upload.
+
+10. **Rollout fraction** *(String, Optional)* - The percentage of users the specified APK will be released to for the specified 'Track'. It can be increased later with the 'Google Play - Increase Rollout' task.
+
+11. **Metadata root directory** *(String, Required)* - The path to the metadata folder with the fastlane metadata structure.
+
+12. **Upload deobfuscation file (mapping.txt)** *(Boolean, Optional)* - Select this option to attach your proguard mapping.txt file to the primary APK.
+
+#### Advanced Options
+
+1. **Replace version codes** *(String, Optional)* - Specify version codes to replace in the selected track with the new APKs: all, the comma separated list, or a regular expression pattern.
+
+    ![Advanced Options](images/bundle-advanced-options.png)
+
+2. **Version code list** *(String, Required if visible)* - The comma separated list of APK version codes to be removed from the track with this deployment. Available options are: *All*, *List* - comma separated list of version codes, *Regular expression* - a regular expression pattern to select a list of APK version codes to be removed from the track with this deployment, e.g. _.\\*12?(3|4)?5_ 
+
+3. **Version code pattern** *(String, Required if visible)* - The regular expression pattern to select a list of APK version codes to be removed from the track with this deployment, e.g. .*12?(3|4)?5