Don't require full CI when `.github/` is the only change (and others)

[mmarchini]

This might also require policy changes on nodejs/node, but for PRs changing Actions we don't need to run full CI. Same goes for PRs changing CODEOWNERS, or linter rules, among other files. I suggest we create a .jenkinsignore file or something on nodejs/node so we can store the rules there instead of here.

[github-actions]

This issue is stale because it has been open many days with no activity. It will be closed soon unless the stale label is removed or a comment is made.