Bump cachix/install-nix-action from 29 to 30

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 29 to 30.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@v29...v30)

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

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -100,7 +100,7 @@ jobs:
             matrix: ${{ steps.set-matrix.outputs.matrix }}
         steps:
             -   uses: actions/checkout@v4
-            -   uses: cachix/install-nix-action@v29
+            -   uses: cachix/install-nix-action@v30
                 with:
                     nix_path: nixpkgs=channel:nixos-24.05
                     extra_nix_config: "system-features = nixos-test benchmark big-parallel kvm"
@@ -131,7 +131,7 @@ jobs:
                         nix-store.nar-${{ runner.os }}-${{ hashFiles('flake.lock') }}-
                         nix-store.nar-${{ runner.os }}-
 
-            -   uses: cachix/install-nix-action@v29
+            -   uses: cachix/install-nix-action@v30
                 with:
                     nix_path: nixpkgs=channel:nixos-24.05
                     extra_nix_config: "system-features = nixos-test benchmark big-parallel kvm"