feat(ci): Use reusable workflow

.forgejo/workflows/check.yaml

@@ -1,22 +0,0 @@
-name: Check
-
-on: [push]
-
-jobs:
-  check:
-    runs-on: ubuntu-latest-amd64
-    steps:
-    - uses: actions/checkout@v3
-    - name: Install Nix
-      uses: https://github.com/DeterminateSystems/nix-installer-action@v4
-      with:
-        init: none
-        planner: linux
-        github-token: null
-    - name: Setup Attic
-      uses: https://github.com/ryanccn/attic-action@v0
-      with:
-        endpoint: ${{ secrets.ATTIC_ENDPOINT }}
-        cache: ${{ secrets.ATTIC_CACHE }}
-        token: ${{ secrets.ATTIC_TOKEN }}
-    - run: nix flake check --keep-going

.github/workflows/ci.yaml

@@ -0,0 +1,8 @@
+name: CI
+
+on: [push]
+
+jobs:
+  flake-check:
+    uses: daniel/reusable-workflows/.github/workflows/nix-flake-check.yaml@main
+    secrets: inherit