nixVersions.nix_2_13: 2.13.2 -> 2.13.3, nixVersions.nix_2_12: 2.12.0 -> 2.12.1

[cole-h]

Description of changes

2.13.3 and 2.12.1 include fixes for writable /etc that was accidentally introduced in 2.12. (see NixOS/nix#7813, NixOS/nix#7830, NixOS/nix#7856)

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.05 Release Notes (or backporting 22.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

---

Waiting for Hydra to go green on maintenance-2.12 and 2.12.1 actually released before this is ready for review.

[K900]

Diff LGTM, /etc no longer writable here

[github-actions]

Backport failed for release-22.11, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally.

git fetch origin release-22.11
git worktree add -d .worktree/backport-218649-to-release-22.11 origin/release-22.11
cd .worktree/backport-218649-to-release-22.11
git checkout -b backport-218649-to-release-22.11
ancref=$(git merge-base f8b026c478c5c2fdd558fc04ea307082ddc30e94 b6290ed97015d2c35060a4369f316c1f0b66654d)
git cherry-pick -x $ancref..b6290ed97015d2c35060a4369f316c1f0b66654d

[cole-h]

Partial backport is at #218664 -- doesn't update the fallback paths or stable alias to prevent breaking anything, and adds 2.13.3 (because 2.13 wasn't there before).