GitProject.get_pr_files_diff inconsistencies

[mfocko]

What happened? What is the problem?

1. Method is tied directly to a PR, should be a method on the PullRequest instead of a method on the GitProject that's relayed to a static method on the PullRequest.
2. Not implemented for GitHub and GitLab.
3. There's no documentation provided for the output of this method, it's just a dict… Ideally define a dataclass and enums for some reasonable interface that could be shared with implementation for other forges too.

What did you expect to happen?

n/a

Example URL(s)

n/a

Steps to reproduce

Workaround

• There is an existing workaround that can be used until this issue is fixed.

Participation

• I am willing to submit a pull request for this issue. (Packit team is happy to help!)