chore(ci): refactor end-to-end test job

Author: Akash Satheesan

.github/workflows/ci.yaml

@@ -174,6 +174,14 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
+      - name: Install node.js v12
+        uses: actions/setup-node@v2
+        with:
+          node-version: "12"
+
+      - name: Install playwright
+        uses: microsoft/playwright-github-action@v1
+
       - name: Download release packages
         uses: actions/download-artifact@v2
         with:
@@ -184,12 +192,20 @@ jobs:
         run: |
           cd release-packages && tar -xzf code-server*-linux-amd64.tar.gz
 
-      - uses: microsoft/playwright-github-action@v1
+      - name: Fetch dependencies from cache
+        id: cache-yarn
+        uses: actions/cache@v2
+        with:
+          path: "**/node_modules"
+          key: yarn-build-${{ hashFiles('**/yarn.lock') }}
+
+      - name: Install dependencies
+        if: steps.cache-yarn.outputs.cache-hit != 'true'
+        run: yarn --frozen-lockfile
 
-      - name: Install dependencies and run end-to-end tests
+      - name: Run end-to-end tests
         run: |
           ./release-packages/code-server*-linux-amd64/bin/code-server &
-          yarn --frozen-lockfile
           yarn test:e2e
 
       - name: Upload test artifacts