chore(ci): bump google-github-actions/auth from 2.1.5 to 2.1.8

Bumps [google-github-actions/auth](https://github.com/google-github-actions/auth) from 2.1.5 to 2.1.8.
- [Release notes](https://github.com/google-github-actions/auth/releases)
- [Changelog](https://github.com/google-github-actions/auth/blob/main/CHANGELOG.md)
- [Commits](google-github-actions/auth@62cf5bd...71f9864)

---
updated-dependencies:
- dependency-name: google-github-actions/auth
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/nightly-build.yaml

@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - name: "Authenticate to Google Cloud (Push to Public registry)"
         id: "gcp-auth"
-        uses: google-github-actions/auth@62cf5bd3e4211a0a0b51f2c6d6a37129d828611d
+        uses: google-github-actions/auth@71f986410dfbc7added4569d411d040a91dc6935
         with:
           workload_identity_provider: ${{ secrets.GCP_WORKLOAD_IDENTITY }}
           service_account: ${{ secrets.GCP_SERVICE_ACCOUNT }}

.github/workflows/release-build.yaml

@@ -16,7 +16,7 @@ jobs:
 
       - name: "Authenticate to Google Cloud (Push to Public registry)"
         id: "gcp-auth"
-        uses: google-github-actions/auth@62cf5bd3e4211a0a0b51f2c6d6a37129d828611d
+        uses: google-github-actions/auth@71f986410dfbc7added4569d411d040a91dc6935
         with:
           workload_identity_provider: ${{ secrets.GCP_WORKLOAD_IDENTITY }}
           service_account: ${{ secrets.GCP_SERVICE_ACCOUNT }}

.github/workflows/traffic.yaml

@@ -60,7 +60,7 @@ jobs:
     #https://github.com/marketplace/actions/authenticate-to-google-cloud#setup
     - id: 'auth'
       name: 'Authenticate to Google Cloud'
-      uses: 'google-github-actions/auth@62cf5bd3e4211a0a0b51f2c6d6a37129d828611d'
+      uses: 'google-github-actions/auth@71f986410dfbc7added4569d411d040a91dc6935'
       with:
         workload_identity_provider: ${{ secrets.GCP_WORKLOAD_IDENTITY }}
         service_account: ${{ secrets.GCP_SERVICE_ACCOUNT }}