Add GitHub merge rules (#71514)
Summary:
Following subfolders of the project were identified as one that can be
merged on github first and then asynchronously merged into Meta
codebase:
## ONNX exporter
PRs that include only files under `torch/onnx`, `torch/csrc/jit/passes/onnx` and `test/onnx` and are reviewed by garymm
## CUDA fusers
PRs that include only files under `torch/csrc/jit/codegen/fuser/cuda`, `torch/csrc/jit/codegen/cuda` or `benchmarks/cpp/nvfuser` and reviewed by csarofeen or ngimel
## OSS CI
PR that include only files under `.circleci`, `.github` and `.jenkins` and reviewed either by seemethere or myself
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71514
Reviewed By: bigfootjon
Differential Revision: D33673050
Pulled By: malfet
fbshipit-source-id: 21b909d49cb73ff79879b3ea0568e53ef65aa08c
(cherry picked from commit 520226c1bf341fe6a9e1cd42f18da73c43386062)
