Add a recommended pipeline example to prevent breakages from advisori…

…es (#22)

README.md

@@ -28,7 +28,7 @@ jobs:
   cargo-deny:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - uses: EmbarkStudios/cargo-deny-action@v1
 ```
 
@@ -41,14 +41,38 @@ jobs:
   cargo-deny:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - uses: EmbarkStudios/cargo-deny-action@v1
       with:
         log-level: warn
         command: check
         arguments: --all-features
 ```
 
+### Recommended pipeline to avoid sudden breakages
+
+```yaml
+name: CI
+on: [push, pull_request]
+jobs:
+  cargo-deny:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        checks:
+          - advisories
+          - bans licenses sources
+
+    # Prevent sudden announcement of a new advisory from failing ci:
+    continue-on-error: ${{ matrix.checks == 'advisories' }}
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: EmbarkStudios/cargo-deny-action@v1
+      with:
+        command: check ${{ matrix.checks }}
+```
+
 ## Users
 
 Repositories using this action (PR to add your repo):