Chore: Migrate yarn from v1 to v2 (#39082)

* Chore: Migrate yarn from v1 to v2

Co-authored-by: Hugo Häggmark <hugo.haggmark@gmail.com>

.github/workflows/publish.yml

@@ -16,16 +16,21 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - run: git clone --single-branch --no-tags --depth 1 -b master https://grafanabot:${{ secrets.GH_BOT_ACCESS_TOKEN }}@github.com/grafana/website-sync ./.github/actions/website-sync
-    - uses: actions/cache@v2.1.6
-      with:
-        path: '**/node_modules'
-        key: ${{ runner.os }}-modules-${{ hashFiles('**/yarn.lock') }}
     - name: generate-packages-docs
       uses: actions/setup-node@v2.4.1
       id: generate-docs
       with:
         node-version: '14'
-    - run: yarn install --pure-lockfile --no-progress
+    - name: Get yarn cache directory path
+      id: yarn-cache-dir-path
+      run: echo "::set-output name=dir::$(yarn config get cacheFolder)"
+    - uses: actions/cache@v2.1.6
+      with:
+        path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
+        key: yarn-${{ hashFiles('**/yarn.lock') }}
+        restore-keys: |
+            yarn-
+    - run: yarn install --immutable
     - run: ./scripts/ci-reference-docs-build.sh
     - name: publish-to-git
       uses: ./.github/actions/website-sync