build(deps): Bump google-github-actions/auth in the actions group

Bumps the actions group with 1 update: [google-github-actions/auth](https://github.com/google-github-actions/auth).


Updates `google-github-actions/auth` from 2.1.5 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@62cf5bd...8254fb7)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/deploy-to-gcs.yml

@@ -23,7 +23,7 @@ jobs:
           tar --directory repository -xvf artifact.tar
 
       # NOTE: This gcloud project/account is NOT the tuf-on-ci online signing account
-      - uses: google-github-actions/auth@62cf5bd3e4211a0a0b51f2c6d6a37129d828611d # v2.1.5
+      - uses: google-github-actions/auth@8254fb75a33b976a221574d287e93919e6a36f70 # v2.1.6
         with:
           token_format: access_token
           workload_identity_provider: projects/306323169285/locations/global/workloadIdentityPools/github-actions-pool/providers/github-actions-provider