GHRepository Can Be Injected into an Action Method

[gcw-it]

Fixes #302

• See title
• Resolved access to deprecated apis in GitHubActionProcessor.java. The sole remaining deprecation warning will sort itself out, when the deprecated api is removed.
• The integration test will execute the real action, when running on GitHub. Locally the repository can't be injected due to the missing environment.
• Documentation will follow

[gcw-it]

@gsmet Are there any capabilities of the GHRepository class you'd like to highlight for the documentation?

[gsmet]

@gcw-it no, I think it's just about making it clear you can easily inject a properly set up GHRepository.

[gcw-it]

Yes, the tests were pretty straight forward, until they weren't :-)

• resolved comments
• added documentation

[gcw-it]

formatting error corrected

[gcw-it]

@gsmet You're welcome