update the authentication to github

At the moment a token should be generated by the user or username and password should be provided which is stored in a file. This approach is not secure enough. So authentication process should be updated.

The issue names no files, tests, or entry points. Locate the current authentication flow and the file storing tokens or credentials, then determine the supported GitHub authentication approach and its security requirements. Done means users can authenticate without storing username/password credentials insecurely and the existing plugin workflow remains usable.

Written by the indexing model from the issue text.