chore(docker): bump google/cloud-sdk

Bumps google/cloud-sdk from 503.0.0-alpine to 504.0.0-alpine.

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

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

Dockerfile

@@ -11,7 +11,7 @@ RUN apk update \
 
 ################################################################################
 
-FROM google/cloud-sdk:503.0.0-alpine
+FROM google/cloud-sdk:504.0.0-alpine
 
 COPY --from=builder /usr/bin/wait-for /usr/bin
 COPY --from=builder /go/bin/pubsubc   /usr/bin