update setup-gcloud github action version (#584)

Author: Mengqi Yu

.github/workflows/release-typegen.yaml

@@ -26,9 +26,11 @@ jobs:
           cd ts/typegen
           make package-typegen
       - name: Set up gcloud
-        uses: GoogleCloudPlatform/github-actions/setup-gcloud@v0.6.0
+        uses: GoogleCloudPlatform/github-actions/setup-gcloud@877d4953d2c70a0ba7ef3290ae968eb24af233bb # 0.6.0
         with:
           version: '388.0.0'
+          # TODO: service_account_email and service_account_key are being deprecated.
+          # We should migrate it to google-github-actions/auth at some time.
           service_account_email: ${{ secrets.GCP_SA_EMAIL }}
           service_account_key: ${{ secrets.GCP_SA_KEY }}
       - name: Upload binaries