Use LTS node on Actions (#46665)

.github/workflows/CI.yml

@@ -2,26 +2,28 @@ name: CI
 on: pull_request
 
 jobs:
-    test:
-        runs-on: ubuntu-latest
+  test:
+    runs-on: ubuntu-latest
 
-        steps:
-            - uses: actions/checkout@v1
-            - uses: actions/setup-node@v1
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions/setup-node@v1
+        with:
+          node-version: "12"
 
-            # Get local dependencies
-            - run: npm install
+      # Get local dependencies
+      - run: npm install
 
-            # Run tests
-            - run: npm run test
+      # Run tests
+      - run: npm run test
 
-            - name: "Run Danger"
-              env:
-                  # See https://github.com/danger/danger-js/issues/1042
-                  DANGER_GITHUB_API_BASE_URL: "https://api.github.com"
+      - name: "Run Danger"
+        env:
+          # See https://github.com/danger/danger-js/issues/1042
+          DANGER_GITHUB_API_BASE_URL: "https://api.github.com"
 
-              # Danger failing (for example through rate-limiting) shouldn't fail the build
-              run: |
-                  TOKEN='7469b4e94ce21b43e3ab7a'
-                  TOKEN+='79960c12a1e067f2ec'
-                  DANGER_GITHUB_API_TOKEN=$TOKEN yarn danger ci || $( exit 0 )
+        # Danger failing (for example through rate-limiting) shouldn't fail the build
+        run: |
+          TOKEN='7469b4e94ce21b43e3ab7a'
+          TOKEN+='79960c12a1e067f2ec'
+          DANGER_GITHUB_API_TOKEN=$TOKEN yarn danger ci || $( exit 0 )