Google Cloud / GCP convenience image

Request for Google Cloud convenience image. We have some custom operations that make it hard to do what we need with just the GCP cli Orb – which I see itself pulls the docker-hosted gcp image google/cloud-sdk so it seems reasonable to have that image hosted by CircleCI that we could use as a base image.

The lack of image caching for non-build steps is one of our biggest pain points currently with CircleCI.