Update clients to handle GitHub Actions

[Pokom]

This is largely pulled from an internal change, and is necessary before cutting over internal usage to the generated container from this project.

Pulled from previous PR:

• Added some more logging + made slog work in GHA (with a default log level of info)
• Use the HEAD^ and HEAD refs as comparisons, the exporter will always create a single commit for a PR
• Updated Drone refs to be GitHub Actions