The transition to the llvm-project monorepo is happening today (LLVM monorepo transition happening on Thursday, the 17th of October). As part of this transition, we have restricted commit access to the following repositories:
These repositories are now effectively read-only, and will not receive any new commits. New commits will be committed to the new https://github.com/apple/llvm-project monorepo which will be set up today. I will update this thread when https://github.com/apple/llvm-project is live and is ready to receive commits.