cmake: 3.12.1 -> 3.12.2

[stites]

Motivation for this change

Trying to use cudatoolkit-10 with magma and running into a bug solved by upgrading cmake. Reference: clab/dynet#1457 (comment)

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

I'm not 100% sure how to test this locally. I tried checking nix path-info -S and nix-shell -p nox --run "nox-review wip". nox returns No uncommit changes. Did you mean to use the "--against" option? and I'm a bit too new at nix to figure it out. I figure this will impact most packages and it might be easier to let CI do this. I have verified the binary on Ubuntu and NixOS, and have passed the current blocker I am facing with magma+cuda-10.

[ttuegel]

@stites Could you please re-make this pull request against the staging branch, because it would cause a mass-rebuild?

[stites]

Will do, I'll also bump to 3.13.4 which is the latest stable cmake release (see #55060). Sorry about the delay!

[stites]

Submitted to staging, see #56059