chore(deps): bump cachix/install-nix-action from 31.8.4 to 31.9.0

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 31.8.4 to 31.9.0.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Changelog](https://github.com/cachix/install-nix-action/blob/master/RELEASE.md)
- [Commits](cachix/install-nix-action@0b0e072...4e002c8)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-version: 31.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/CI.yml

@@ -152,7 +152,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Install nix
-        uses: cachix/install-nix-action@0b0e072294b088b73964f1d72dfdac0951439dbd # v31.8.4
+        uses: cachix/install-nix-action@4e002c8ec80594ecd40e759629461e26c8abed15 # v31.9.0
         with:
           nix_path: nixpkgs=channel:nixos-unstable
       - name: Install dependencies