Possibility to connect as another user account

[Du-St]

You can use this option when connecting using --service-account. Filling
the Google account username into --service-account-subject you will be
connected as this Google account instead of the service account.

Required settings on the Google site:

1. Service account must be domain-wide delegated (Google APIs > IAM & Admin > Service accounts > Edit service account > check "Enable GSuite
   Domain-wide Delegation". Also new OAuth 2.0 client will be created.
2. There must be allowed SDK API in the GDrive settings (Admin Console >
   Apps > GSuite > Drive and Docs > Data access > check "Allow Drive SDK
   API"
3. The newly created OAuth 2.0 client must be allowed in the GSuite security
   settings to use GDrive API (Admin Console > Security > Show more >
   Advanced settings > click Manage API client access > fill the form:

• Client ID is the client id found in Google APIs > APIs & Services >
  Credentials
• One or more API Scopes is "https://www.googleapis.com/auth/drive"

[Du-St]

Hi,

I have added the possibility to impersonate (connect as another user) when connecting using service account.

The key change is setting the Subject property of the jwt.Config type.

[naxvog]

Just a little addendum to the Guide given:
If you followed all steps and you still can not impersonate due to missing permissions, creating a new google project and follow the steps again did the trick.
My project was quite old so I guess there was a migration or corruption issue within the google project.

Needless to say: Ty for the PR, saved my life