krane/gcrane: Add --impersonate-service-account flag #2222
Description
I have a use case at work where we have credentials to authenticate with a service account that only has permissions to impersonate other service accounts, and then we need to use that account to impersonate different service accounts based on which permissions we need for a particular action.
Currently, the only way to do this is to use the gcloud CLI to set a service account or manually edit the ADC file to specify an impersonated service account. This is less than ideal in my opinion and I think it would be nice to have a flag for this, as mentioned in #1375 (comment).