On Windows, when doing gcloud auth configure-docker, it will add be something like "us-east1-docker.pkg.dev": "gcloud" in config.json.
This works perfectly with docker command line but the docker-maven-plugin doesn't like it when running a build from PowerShell for instance.
You need to use gcloud.cmd in config.json since the executable is docker-credential-gcloud.cmd. Note that this might break usage in git bash. I haven't tried yet.