Bump google-github-actions/auth from 2.1.3 to 2.1.6

Bumps [google-github-actions/auth](https://github.com/google-github-actions/auth) from 2.1.3 to 2.1.6.
- [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@v2.1.3...v2.1.6)

---
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/ci.yml

@@ -20,7 +20,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: true
-      - uses: google-github-actions/[email protected].3
+      - uses: google-github-actions/[email protected].6
         with:
           workload_identity_provider: '${{ secrets.WORKLOAD_IDENTITY_POOL_PROVIDER }}'
           service_account: '${{ secrets.CONTAINER_IMAGE_BUILDER_SERVICE_ACCOUNT_ID }}'
@@ -108,7 +108,7 @@ jobs:
           helm template chart/ > helm-output.yaml
           kustomize create --resources helm-output.yaml
           kustomize build .
-      - uses: google-github-actions/[email protected].3
+      - uses: google-github-actions/[email protected].6
         with:
           workload_identity_provider: '${{ secrets.WORKLOAD_IDENTITY_POOL_PROVIDER }}'
           service_account: '${{ secrets.CONTAINER_IMAGE_BUILDER_SERVICE_ACCOUNT_ID }}'