ci: Switch to omnix

Author: srid

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ jobs:
     steps:
      - uses: actions/checkout@v4
      - id: set-matrix
-       run: echo "matrix=$(nixci gh-matrix --systems=x86_64-linux,x86_64-darwin,aarch64-darwin | jq -c .)" >> $GITHUB_OUTPUT
+       run: echo "matrix=$(om ci gh-matrix --systems=x86_64-linux,x86_64-darwin,aarch64-darwin | jq -c .)" >> $GITHUB_OUTPUT
 
   nix:
     runs-on: ${{ matrix.system }}
@@ -29,8 +29,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - run: |
-          nixci \
+          om ci \
             --extra-access-tokens "github.com=${{ secrets.GITHUB_TOKEN }}" \
-            build \
-            --systems "github:nix-systems/${{ matrix.system }}" \
+            run \
+            --systems "${{ matrix.system }}" \
             .#default.${{ matrix.subflake}}