Bump google-github-actions/auth from 0.6.0 to 0.7.0 (sigstore#1712)

Bumps [google-github-actions/auth](https://github.com/google-github-actions/auth) from 0.6.0 to 0.7.0.
- [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@8d12589...50dbfd0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build.yaml

@@ -48,7 +48,7 @@ jobs:
         run: go get golang.org/x/tools/cmd/goimports
 
       - name: Set up Cloud SDK
-        uses: google-github-actions/auth@8d125895b958610ec414ca4dae010257eaa814d3 # v0.6.0
+        uses: google-github-actions/auth@50dbfd0907520dcccbd51e965728eb32e592b8fa # v0.6.0
         with:
           workload_identity_provider: 'projects/498091336538/locations/global/workloadIdentityPools/githubactions/providers/sigstore-cosign'
           service_account: 'github-actions@projectsigstore.iam.gserviceaccount.com'