[libcxx-commits] [libcxx] [libc++] Update the CMake version we use in the CI (PR #215783)

[Louis Dionne via libcxx-commits]

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

LGTM. I'll edit the PR description to mention the RFC (https://discourse.llvm.org/t/rfc-raising-minimum-required-cmake-version-to-3-31/91086)

https://github.com/llvm/llvm-project/pull/215783