[llvm] DeveloperPolicy: Update commit access requirements (PR #127006)

[Louis Dionne via llvm-commits]

https://github.com/ldionne approved this pull request.

LGTM, thanks for seeking this consensus!

I have some suggestions that IMO improve things a bit further, but I'm also fine with this being merged as-is and my comments being addressed in a follow-up, or not at all.

https://github.com/llvm/llvm-project/pull/127006