chore: migrate yarn modern to npm registry corepack (cypress-io#1420)

Author: MikeMcC399

.github/workflows/example-yarn-modern-pnp.yml

@@ -12,13 +12,20 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - run: corepack enable yarn # experimental - see https://nodejs.org/docs/latest/api/corepack.html
+      - name: Enable Corepack # see https://yarnpkg.com/getting-started/install
+        run: |
+          npm install -g corepack
+          corepack enable yarn
       - name: Set up Yarn cache
         uses: actions/setup-node@v4
         with:
           node-version-file: '.node-version'
           cache: yarn
           cache-dependency-path: examples/yarn-modern-pnp/yarn.lock
+      - name: Reinstall Corepack # actions/setup-node may have replaced Corepack with an older version
+        run: |
+          npm install -g corepack
+          corepack enable yarn
       - name: Custom Yarn command
         uses: ./
         with:

.github/workflows/example-yarn-modern.yml

@@ -12,13 +12,20 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - run: corepack enable yarn # experimental - see https://nodejs.org/docs/latest/api/corepack.html
+      - name: Enable Corepack # see https://yarnpkg.com/getting-started/install
+        run: |
+          npm install -g corepack
+          corepack enable yarn
       - name: Set up Yarn cache
         uses: actions/setup-node@v4
         with:
           node-version-file: '.node-version'
           cache: yarn
           cache-dependency-path: examples/yarn-modern/yarn.lock
+      - name: Reinstall Corepack # actions/setup-node may have replaced Corepack with an older version
+        run: |
+          npm install -g corepack
+          corepack enable yarn
       - name: Custom Yarn command
         uses: ./
         with:

docs/MAINTENANCE.md

@@ -20,7 +20,7 @@ _The previous [examples/v9](https://github.com/cypress-io/github-action/tree/v5/
 
 - [npm](https://www.npmjs.com/), which is installed with [Node.js](https://nodejs.org/).
 
-- [corepack](https://github.com/nodejs/corepack), which is installed with [Node.js](https://nodejs.org/).
+- [corepack](https://github.com/nodejs/corepack). This is currently installed with [Node.js](https://nodejs.org/). Due to plans of Node.js to remove it in versions Node.js `25.x` and later, you may need to install it separately with `npm install -g corepack`.
 
 - [pnpm](https://pnpm.io/) installed through:
 

examples/yarn-modern-pnp/README.md

@@ -5,6 +5,7 @@ This example demonstrates installing dependencies using [Yarn Modern v4](https:/
 Run locally with:
 
 ```shell
+npm install -g corepack
 corepack enable yarn
 yarn
 yarn test

examples/yarn-modern/README.md

@@ -5,6 +5,7 @@ This example demonstrates installing dependencies using [Yarn Modern v4](https:/
 Run locally with:
 
 ```shell
+npm install -g corepack
 corepack enable yarn
 yarn
 yarn test