build(deps): bump google.com/cloudsdktool/google-cloud-cli (#6889)

Bumps google.com/cloudsdktool/google-cloud-cli from 507.0.0-emulators to 508.0.0-emulators.

---
updated-dependencies:
- dependency-name: google.com/cloudsdktool/google-cloud-cli
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

docker/images/pubsub-emulator/Dockerfile

@@ -1,3 +1,3 @@
 # Define this image outside of docker-compose.yml so that it gets dependabot updates
-FROM gcr.io/google.com/cloudsdktool/google-cloud-cli:507.0.0-emulators@sha256:2bd03a5f1fd06906ffba118b7b0630bcc61c41f4a55dfceaf38495baeeb3caef
+FROM gcr.io/google.com/cloudsdktool/google-cloud-cli:508.0.0-emulators@sha256:2884f89dc7b1487ecb84f99a5e908c4505a03d84198e202b166e61b409859c68
 # also available as google/cloud-sdk:<version>-emulators