chore(deps): Bump DeterminateSystems/magic-nix-cache-action from 2 to 3

Bumps [DeterminateSystems/magic-nix-cache-action](https://github.com/determinatesystems/magic-nix-cache-action) from 2 to 3.
- [Release notes](https://github.com/determinatesystems/magic-nix-cache-action/releases)
- [Commits](DeterminateSystems/magic-nix-cache-action@v2...v3)

---
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.yml

@@ -80,7 +80,7 @@ jobs:
       - name: Install Nix
         uses: DeterminateSystems/nix-installer-action@v9
       - name: Cache Nix dependencies
-        uses: DeterminateSystems/magic-nix-cache-action@v2
+        uses: DeterminateSystems/magic-nix-cache-action@v3
       - name: Setup developer environment
         run: |
           nix develop --command ./bootstrap.sh

.github/workflows/nix.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Install Nix
         uses: DeterminateSystems/nix-installer-action@v9
       - name: Cache Nix dependencies
-        uses: DeterminateSystems/magic-nix-cache-action@v2
+        uses: DeterminateSystems/magic-nix-cache-action@v3
       # Upstream package sometimes has flags set that disable flake checking
       - name: Setup test env
         run: |