feat: add push-to-gcr action

.github/workflows/deploy-main.yml

@@ -5,6 +5,10 @@ on:
     branches:
       - main
 
+permissions:
+  id-token: write
+  contents: read
+
 concurrency:
   group: 'fast-auth-signer-deployment'
   cancel-in-progress: true
@@ -27,3 +31,7 @@ jobs:
     with:
       environment: mainnet
     secrets: inherit
+
+  deploy-docker-image-to-gcr:
+    uses: ./.github/workflows/push-to-gcr.yml
+    secrets: inherit

.github/workflows/push-to-gcr.yml

@@ -0,0 +1,28 @@
+name: Push to GCR GitHub Action
+
+on:
+  workflow_call:
+
+permissions:
+  id-token: write
+  contents: read
+
+jobs:
+  build-and-push-to-gcr:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: 'read'
+      id-token: 'write'
+    steps:      
+      - uses: actions/checkout@v3
+      - name: Authenticate to Google Cloud
+        id: auth
+        uses: google-github-actions/auth@v1
+        with:
+          credentials_json: ${{ secrets.SERVICE_ACCOUNT_KEY_JSON }}
+      - uses: RafikFarhad/push-to-gcr-github-action@v5-beta
+        with:
+          registry: gcr.io
+          project_id: fast-auth-sdk
+          image_name: frontend
+          image_tag: latest