Bump DeterminateSystems/nix-installer-action from 8 to 9

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 8 to 9.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@v8...v9)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/nix.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Install Nix
-      uses: DeterminateSystems/nix-installer-action@v8
+      uses: DeterminateSystems/nix-installer-action@v9
     - name: Run the Magic Nix Cache
       uses: DeterminateSystems/magic-nix-cache-action@v2