Bump cachix/install-nix-action from V27 to 28

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from V27 to 28. This release includes the previously tagged commit.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@V27...V28)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-type: direct:production
...

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

.github/workflows/update-flake-lock.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

.github/workflows/workflow.yaml

@@ -36,7 +36,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@V27
+      - uses: cachix/install-nix-action@V28
         with:
           nix_path: nixpkgs=./docs/nixpkgs.nix
       - uses: ./.github/actions/configure_bazelrc
@@ -80,7 +80,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@V27
+      - uses: cachix/install-nix-action@V28
         with:
           nix_path: nixpkgs=./nixpkgs.nix
       - uses: ./.github/actions/configure_bazelrc