feat: implement version-related APIs for GeneratorAPI (#4000)

closes #2336

(cherry picked from commit 77092b2223)

docs/dev-guide/generator-api.md

@@ -1,5 +1,44 @@
 # Generator API
 
+## cliVersion
+
+Type: `string`
+
+The version string for the **global** `@vue/cli` version that is invoking the plugin.
+
+
+## assertCliVersion
+
+- **Arguments**
+  - `{integer | string} range` - a semver range that `@vue/cli` needs to satisfy
+
+- **Usage**
+
+  While api.version can be useful in general, it's sometimes nice to just declare your version.
+  This API exposes a simple way to do that.
+
+  Nothing happens if the provided version is satified. Otherwise, an error will be thrown.
+
+
+## cliServiceVersion
+
+Type: `string`
+
+The version string for the **project local** `@vue/cli-service` version that is invoking the plugin.
+
+
+## assertCliServiceVersion
+
+- **Arguments**
+  - `{integer | string} range` - a semver range that `@vue/cli-service` needs to satisfy
+
+- **Usage**
+
+  This API exposes a simple way to declare the required project local `@vue/cli-service` version.
+
+  Nothing happens if the provided version is satified. Otherwise, an error will be thrown.
+
+
 ## resolve
 
 - **Arguments**

docs/dev-guide/plugin-api.md

@@ -7,7 +7,7 @@ Type: `string`
 The version string for the `@vue/cli-service` version that is loading the plugin.
 
 
-## assertVersion(range)
+## assertVersion
 
 - **Arguments**
   - `{integer | string} range` - a semver range that `@vue/cli-service` needs to satisfy