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](DeterminateSystems/magic-nix-cache-action@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] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -19,7 +19,7 @@ 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
       - id: set-matrix
         name: Generate Nix Matrix
         run: |
@@ -38,7 +38,7 @@ 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
       - run: nix build -L ".#${{ matrix.attr }}" --keep-going
 
       - name: Twister Tests