Fix: pin gcloud cli alpine image tag

[andrewmackett]

The latest gcr.io/google.com/cloudsdktool/cloud-sdk:alpine image fails to run gcloud run services list command:

ERROR: gcloud failed to load (gcloud.run.services): Problem loading gcloud.run.services: No module named 'grpc'.

This usually indicates corruption in your gcloud installation or problems with your Python interpreter.

Please verify that the following is the path to a working Python 3.9+ executable:
    /usr/bin/python3
If it is not, please set the CLOUDSDK_PYTHON environment variable to point to a working Python 3.9+ executable.

If you are still experiencing problems, please run the following command to reinstall:
    $ gcloud components reinstall

If that command fails, please reinstall the Google Cloud CLI using the instructions here:
    https://cloud.google.com/sdk/

It looks like this issue was introduced in the 541.0.0-alpine tag; to work around, you can pin to the 540.0.0-alpine tag:

docker run --rm gcr.io/google.com/cloudsdktool/google-cloud-cli:541.0.0-alpine gcloud run services list --help
ERROR: gcloud failed to load (gcloud.run.services): Problem loading gcloud.run.services: No module named 'grpc'.
...

docker run --rm gcr.io/google.com/cloudsdktool/google-cloud-cli:540.0.0-alpine gcloud run services list --help
NAME
    gcloud run services list - list available services
...

We've opened a GitHub issue to get this resolved.

As a workaround, we're moving to use the 540.0.0-alpine tag.

_{This PR was generated using turbolift.}