Support of Azure Workload Identity for Repo Auth

[r-gg]

Currently the image updater only uses username/password [ i.e. Azure DevOps PAT ] authentication with the Git Repos [ Azure Repos ] ~ when it needs to push for example. As I would like to use a Service Principal to push the changes into the repo, this is currently not possible, since Azure Devops only allows PATs for Users (and not SPs).

Adding workload identity as a method of authentication to these Repos would fix the issue. ~ ArgoCD already does this with Azure Repos:
https://argo-cd.readthedocs.io/en/stable/user-guide/private-repositories/#azure-container-registryazure-repos-using-azure-workload-identity

Version
This feature request applies to v1.1.1.:

• Annotation-based configuration (versions starting with 0, e.g., 0.17.0)
• CRD-based configuration (versions starting with 1, e.g., 1.0.0)

[felfa01]

This would be a great addition. If you have configured the ArgoCD Repository secret with Azure Workload Identity you need to keep a separate, PAT-based authentication step for ArgoCD Image Updater. Adds complexity and another attack vector.