dynamic ci matrix

.github/workflows/ci.yml

@@ -29,15 +29,22 @@ jobs:
           authToken: '${{ secrets.ATTIC_TOKEN }}'
       - run: nix build .#clippy
 
+  matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - uses: actions/checkout@v3
+      - uses: cachix/install-nix-action@v20
+      - id: set-matrix
+        run: echo "matrix={\"target\":$(nix eval --json ".#targets.x86_64-linux")}" | tee $GITHUB_OUTPUT
+
   build:
     runs-on: ubuntu-latest
-    needs: check
+    needs: [matrix, check]
     strategy:
       fail-fast: false
-      matrix:
-        target:
-          - x86_64-unknown-linux-gnu
-          - x86_64-unknown-linux-musl
+      matrix: ${{fromJson(needs.matrix.outputs.matrix)}}
     steps:
       - uses: actions/checkout@v3
       - uses: cachix/install-nix-action@v20