Added option to enable corepack (#1)

Co-authored-by: Steven <steven@ceriously.com>
Co-authored-by: Sayak Mukhopadhyay <mukhopadhyaysayak@gmail.com>
Co-authored-by: Jacob Parish <jacob.parish.1@gmail.com>

docs/advanced-usage.md

@@ -416,3 +416,32 @@ Please refer to the [Ensuring workflow access to your package - Configuring a pa
 
 ### always-auth input
 The always-auth input sets `always-auth=true` in .npmrc file. With this option set [npm](https://docs.npmjs.com/cli/v6/using-npm/config#always-auth)/yarn sends the authentication credentials when making a request to the registries.
+
+## Enabling Corepack
+You can enable [Corepack](https://github.com/nodejs/corepack) by using the `corepack` input. You can then use `pnpm` and `yarn` commands in your project.
+
+```yaml
+steps:
+- uses: actions/checkout@v3
+- uses: actions/setup-node@v3
+  with:
+    node-version: '16.x'
+    corepack: true
+- name: Install dependencies
+  run: yarn install --immutable
+```
+
+You can also pass package manager names separated by a space to enable corepack for specific package managers only.
+
+```yaml
+steps:
+- uses: actions/checkout@v3
+- uses: actions/setup-node@v3
+  with:
+    node-version: '16.x'
+    corepack: yarn pnpm
+- name: Install dependencies
+  run: yarn install --immutable
+```
+
+This option by default is `false` as Corepack is still in experimental phase.