[llvm] [Github][OpenMP] Adding rule for OpenMP label (PR #65331)

[Jan Patrick Lehr via llvm-commits]

jplehr wrote:

I have updated this once more with
- updated patterns for paths to follow the `foo/**` syntax as it seems to have been preferred in this file,
- a glob pattern in the two runtime labels. I believe that this was necessary to cover all paths under the respective top-level directory, e.g., `openmp/libomptarget/**`.

I'm going to create the new labels and merge this later today. Please feel free to comment.

https://github.com/llvm/llvm-project/pull/65331