GitHub action to add labels when PR has conflicts

[aaron-hopkinson]

Is your feature request related to a problem? Please describe.

It isn't clear from the main GitHub pull request list when a PR has accrued conflicts. It would be nice to be able to see this at a glance, so we can try to keep PRs in a mergeable state. This would ease the burden on both authors and reviewers, and help tp prevent a delay when a reviewer goes to review a PR and has go back to the author to ask them to resolve the commits.

Describe the solution you'd like

PRs should have a label that is automatically added/removed marking when a PR has a merge conflict.

Describe alternatives you've considered

There already exist a number of GitHub Actions that can do this, see: https://github.com/marketplace?type=actions&query=conflict

Additional context

No response

Organisation

ECMWF

[aaron-hopkinson]

NB: The PyCharm already has an icon to denote when a PR has a conflict in its GitHub view (not sure about VScode) – so from my personal perspective this isn't high priority.