dedupe nix cache

.github/actions/nix-setup/action.yml

@@ -0,0 +1,8 @@
+name: 'Setup Nix'
+description: 'Install Nix with DeterminateSystems and enable magic-nix-cache'
+
+runs:
+  using: composite
+  steps:
+    - uses: DeterminateSystems/nix-installer-action@ef8a148080ab6020fd15196c2084a2eea5ff2d25 # v22
+    - uses: DeterminateSystems/magic-nix-cache-action@565684385bcd71bad329742eefe8d12f2e765b39 # v13

.github/workflows/nix-lockfile-check.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
 
-      - uses: nixbuild/nix-quick-install-action@63ca48f939ee3b8d835f4126562537df0fee5b91  # v30
+      - uses: ./.github/actions/nix-setup
 
       - name: Resolve head SHA
         id: sha

.github/workflows/nix-lockfile-fix.yml

@@ -98,7 +98,7 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           fetch-depth: 0
 
-      - uses: nixbuild/nix-quick-install-action@63ca48f939ee3b8d835f4126562537df0fee5b91  # v30
+      - uses: ./.github/actions/nix-setup
 
       - name: Apply lockfile hashes
         id: apply

.github/workflows/nix.yml

@@ -21,8 +21,7 @@ jobs:
     timeout-minutes: 30
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
-      - uses: DeterminateSystems/nix-installer-action@ef8a148080ab6020fd15196c2084a2eea5ff2d25 # v22
+      - uses: ./.github/actions/nix-setup
-      - uses: DeterminateSystems/magic-nix-cache-action@565684385bcd71bad329742eefe8d12f2e765b39 # v13
       - name: Check flake
         if: runner.os == 'Linux'
         run: nix flake check --print-build-logs