Advertise USE_PRECOMPILED_HEADERS in CONTRIBUTING.md (#62827)
Summary:
This option was added in https://github.com/pytorch/pytorch/issues/61940 and fits with this section's theme of improving build times.
I've also changed it to a `cmake_dependent_option` instead of `FATAL_ERROR`ing for older CMake versions.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62827
Reviewed By: astaff
Differential Revision: D30342102
Pulled By: malfet
fbshipit-source-id: 3095b44b7085aee8a884ec95cba9f8998d4442e7
