Refactored to use google-github-actions/auth@v2

Signed-off-by: Andre Wanlin <[email protected]>

.github/workflows/techdocs.yml

@@ -14,20 +14,24 @@ concurrency:
 jobs:
   publish-techdocs-site:
     runs-on: ubuntu-latest
-
+    permissions:
+      contents: 'read'
+      id-token: 'write'
     steps:
       - name: Checkout Backstage
         uses: actions/checkout@v3
         with:
           repository: backstage/backstage
           fetch-depth: 1
 
-      - name: use node.js 18.x
+      - name: Use Node 18.x
         uses: actions/setup-node@v3
         with:
           node-version: 18.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
-      - uses: actions/setup-python@v4
+
+      - name: Use Python 3.9
+        uses: actions/setup-python@v4
         with:
           python-version: '3.9'
 
@@ -40,7 +44,9 @@ jobs:
       - name: Generate docs site
         run: techdocs-cli generate --no-docker --verbose
 
+      - name: Login to GCS
+        uses: 'google-github-actions/auth@v2'
+        with:
+          credentials_json: ${{ secrets.TECHDOCS_GCS_CREDENTIALS_JSON }}
       - name: Publish docs site
         run: techdocs-cli publish --publisher-type googleGcs --storage-name ${{ secrets.TECHDOCS_GCS_BUCKET }} --entity default/component/backstage
-        env:
-          GOOGLE_APPLICATION_CREDENTIALS: ${{ secrets.GOOGLE_APPLICATION_CREDENTIALS }}