[llvm] [LLVM] Update cmake maintainer (PR #120542)

[Chris B via llvm-commits]

llvm-beanz wrote:

> It's a bit weird that I'm still here... I thought @llvm-beanz had taken this over officially some time ago? Maybe I'm mis-remembering?

For historical context, even though I was doing all that work to kill autoconf, I deliberately did not _want_ to be the owner. I really enjoyed being able to tell people ether @chandlerc was the code owner so when they had problems they could blame him 😝. Clearly people kept blaming me, so my strategy didn't work.

https://github.com/llvm/llvm-project/pull/120542