Updates CMake to 3.30.2

[Mottl]

This commit updates CMake to 3.30.2 and fixes rust-lang/docs.rs#2587

[Mottl]

@syphar, now I think it's good to review

[syphar]

cross-post from rust-lang/docs.rs#2587 (comment)

I'm sorry if I wasn't clear enough in my messages above.
Right now we only accept standard ubuntu packages into the builder image due to the maintenance / security burden.
So upgrading to the latest LTS is the way to solve this issue.

An alternative is to work on rust-lang/docs.rs#315 (allow custom docker images), but my hunch is that upgrading the main build env is less work.

[Mottl]

Closed due to #151