[llvm] [Workflow] Add new code format helper. (PR #66684)

[Tobias Hieta via llvm-commits]

tru wrote:

> My PR fails in this new CI target because `llvm/utils/git/requirements_formatting.txt` cannot be found. See output [here](https://github.com/llvm/llvm-project/actions/runs/6284641620/job/17066205762?pr=67241). I have rebased just now. Am I doing something wrong?

No that's me testing some other fixes. It should be fixed now. But you might have to rebase your change on main to get the latest fix. 

https://github.com/llvm/llvm-project/pull/66684