Bump DeterminateSystems/nix-installer-action from 6 to 8 (#1144)

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 6 to 8.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@v6...v8)

---
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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/release.yml

@@ -36,7 +36,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v6
+        uses: DeterminateSystems/nix-installer-action@v8
 
       - name: Configure Cachix
         uses: cachix/cachix-action@v12