Rename ArrayOrString to ParamValues

This commit fixes issue tektoncd#4858. With the implementation of Tep75,
ArrayOrString contains object type and it would be confusing if still
use the same name. This commit renames it to ParamValues and type alias
ResultValues to ParamValues. Also use type alias to make sure dependant
libraries can still use ArrayOrString and NewArrayOrString.

docs/api-spec.md

@@ -14,7 +14,7 @@
 - [Status Signalling](#status-signalling)
 - [Listing Resources](#listing-resources)
 - [Detailed Resource Types - v1beta1](#detailed-resource-types---v1beta1)
-  * [`ArrayOrString`](#arrayorstring)
+  * [`ParamValue`](#paramvalue)
   * [`ContainerStateRunning`](#containerstaterunning)
   * [`ContainerStateWaiting`](#containerstatewaiting)
   * [`ContainerStateTerminated`](#containerstateterminated)
@@ -186,13 +186,14 @@ List responses have the following fields (based on [`meta.v1/ListMeta`](https://
 
 ## Detailed Resource Types - v1beta1
 
-### `ArrayOrString`
+### `ParamValue`
 
 | Field Name  | Field Type | Requirement |
 |-------------|------------|-------------|
-| `type`      | Enum:<br>- `"string"` (default)<br>- `"array"` | REQUIRED |
+| `type`      | Enum:<br>- `"string"` (default)<br>- `"array"` <br>- `"object"` | REQUIRED |
 | `stringVal` | string     | REQUIRED    |
 | `arrayVal`  | []string   | REQUIRED    |
+| `objectVal` | map<string,string>   | REQUIRED    |
 
 ### `ContainerStateRunning`
 
@@ -235,7 +236,7 @@ List responses have the following fields (based on [`meta.v1/ListMeta`](https://
 | Field Name | Field Type      | Requirement |
 |------------|-----------------|-------------|
 | `name`     | string          | REQUIRED    |
-| `value`    | `ArrayOrString` | REQUIRED    |
+| `value`    | `ParamValue` | REQUIRED    |
 
 ### `ParamSpec`
 
@@ -244,7 +245,7 @@ List responses have the following fields (based on [`meta.v1/ListMeta`](https://
 | `name`        | string     | REQUIRED    |
 | `description` | string     | REQUIRED    |
 | `type`        | Enum: <br>- `"string"` (default) <br>- `"array"` | REQUIRED |
-| `default`     | `ArrayOrString` | REQUIRED |
+| `default`     | `ParamValue` | REQUIRED |
 
 ### `Step`