Authentication tokens from credential helpers incorrectly used as passwords

[wrosenuance]

Description

The documentation for docker login at https://github.com/docker/docker-ce/blob/master/components/cli/docs/reference/commandline/login.md says:

If the secret being stored is an identity token, the Username should be set to <token>

This means that when a credential helper response is returned with the username equal to <token>, the AuthConfig constructed should use the identity token constructor instead of the username/password constructor.

This is similar to #1249, except there the credentials were stored in config.json, while here they are returned from a credential helper.

• d-m-p version : 0.33-SNAPSHOT

• Maven version (mvn -v) : 3.6.3 (and others, I expect)

• If it's a bug, how to reproduce :

When using an Azure Container Registry and a credential helper, run az acr login -n <acr-name> to retrieve an authentication token and store in the credential helper.

Then, run a docker-maven-plugin:push that needs to use the credentials. It will fail with message like Unable to push 'example-image:latest' to registry 'acrname.azurecr.io' : unauthorized: aad access token with sp failed unknown error [unauthorized: aad access token with sp failed unknown error ].