Email address for git commits in Flows does not exist.

Problem to solve

Executor sets the email address for the user to duo.workflow.agent@gitlab.com, see here

Here is an example.

It's not a great User Experience to see this email for the commit author.

Proposal

Set the email adress to the one of the service account used by the composite identity if that's available.

Implementation plan

Potential approach:

1. pull the email from an ENV var: https://gitlab.com/gitlab-org/duo-workflow/duo-workflow-executor/-/blob/8bd14e5d9a83bf56fb2bb28b955ffb412f697fc5/main.go#L93
2. I'm not sure the details of Composite Identity, but assuming we can get the email here, then it should be straightforward to pass it along the executor here.

Links / references