Is your feature request related to a problem? Please describe.
ArgoCD v2.6.0-rc1 introduced a new field called sources, which overrides the source field of the application resource. When setting image-updater on such application, we get:
level=warning msg="skipping app 'myapp-staging' of type '' because it's not of supported source type" application=myapp-staging
which indicates that image-updater does not recognize this application as of valid source type.
Describe the solution you'd like
Seems like a minor update could make image-updater aware of this new sources field and apply some logic accordingly

Describe alternatives you've considered
Couldn't find any

Additional context
None