updates to creating a release PR

[TomasTomecek]

TODO

• don't create duplicate commits in case of failures (in packit/ogr, bot was not allowed to create a PR and kept adding new commits; we should reset --hard upstream/master before starting adding new commits)
• ditch our github client implementation for packit/ogr
• fork the repo and create the PR from fork
• remove branches once they are merged
• create changelog.md if it's not present (should be configurable)

[lachmanfrantisek]

What about creating the CHANGELOG.md if the file does not exist?

[TomasTomecek]

could you elaborate please?

[lachmanfrantisek]

could you elaborate please?

Is CHANGELOG.md already present?

• NO -> Create the file and add the changes for the current release.
• YES -> Add new changes on top of the file as usual. (already implemented)

[TomasTomecek]

I added one more entry to the list, let me know if that's what you meant, because r-bot is already doing the YES branch afaik