ci: 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] <support@github.com>

.github/workflows/ci.yaml

@@ -37,7 +37,7 @@ jobs:
         uses: DeterminateSystems/nix-installer-action@v16
 
       - name: Setup Nix cache
-        uses: DeterminateSystems/magic-nix-cache-action@v8
+        uses: DeterminateSystems/magic-nix-cache-action@v9
 
       - name: Run build
         run: |
@@ -56,7 +56,7 @@ jobs:
         uses: DeterminateSystems/nix-installer-action@v16
 
       - name: Setup Nix cache
-        uses: DeterminateSystems/magic-nix-cache-action@v8
+        uses: DeterminateSystems/magic-nix-cache-action@v9
 
       - name: Run flake checks
         run: |

.github/workflows/clippy.yaml

@@ -35,7 +35,7 @@ jobs:
         uses: DeterminateSystems/nix-installer-action@v16
 
       - name: Setup Nix cache
-        uses: DeterminateSystems/magic-nix-cache-action@v8
+        uses: DeterminateSystems/magic-nix-cache-action@v9
 
       - name: Run clippy
         id: clippy-run