Use built in yarn caching in GH actions

.github/workflows/ci.yml

@@ -11,22 +11,11 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
-      - name: Setup yarn cache directory
-        id: yarn-cache
-        run: echo "::set-output name=dir::$(yarn cache dir)"
-
-      - name: Setup yarn cache
-        uses: actions/cache@v2
-        with:
-          path: ${{ steps.yarn-cache.outputs.dir }}
-          key: ${{ runner.os }}-yarn
-          restore-keys: |
-            ${{ runner.os }}-yarn
-
       - name: Setup Node.js
         uses: actions/setup-node@v2
         with:
           node-version: 16.x
+          cache: 'yarn'
 
       - run: yarn install
       - run: yarn verify