build(deps): bump DeterminateSystems/magic-nix-cache-action from 8 to 9

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

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

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

.github/workflows/build-devcontainers.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: DeterminateSystems/nix-installer-action@v16
-      - uses: DeterminateSystems/magic-nix-cache-action@v8
+      - uses: DeterminateSystems/magic-nix-cache-action@v9
         with:
           extra-conf: |
             keep-going = true

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: DeterminateSystems/nix-installer-action@v16
-      - uses: DeterminateSystems/magic-nix-cache-action@v8
+      - uses: DeterminateSystems/magic-nix-cache-action@v9
         with:
           extra-conf: |
             keep-going = true

.github/workflows/iso.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: DeterminateSystems/nix-installer-action@v16
-      - uses: DeterminateSystems/magic-nix-cache-action@v8
+      - uses: DeterminateSystems/magic-nix-cache-action@v9
       - name: Build ISO
         run: |
           nix build .#images.${{ matrix.arch }}.bootstrap-install-iso --impure --out-link build-iso-result

.github/workflows/site.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: DeterminateSystems/nix-installer-action@v16
-      - uses: DeterminateSystems/magic-nix-cache-action@v8
+      - uses: DeterminateSystems/magic-nix-cache-action@v9
       - env:
           NIXPKGS_ALLOW_UNFREE: "1"
         run: nix build .#devPackages.x86_64-linux.website