[libcxx-commits] [libcxx] [llvm] [libc++][CI] Moves CI badge to main README. (PR #77247)

[Tom Stellard via libcxx-commits]

https://github.com/tstellar approved this pull request.

This is fine with me.   If people don't like it we can always move it somewhere else.

https://github.com/llvm/llvm-project/pull/77247