update forgejo workflow

.forgejo/workflows/build.yaml

@@ -3,15 +3,14 @@ on:
   - push
 jobs:
   build:
-    runs-on: ubuntu-latest
-    container: docker.io/jcollie/nixos-runner:latest
+    runs-on: nixos
     steps:
       - uses: actions/checkout@v4
       - run: set
       - run: nix build -L .#nixos-runner
       - run: nix run .#push-container -- result
         env:
-          REGISTRY: https://git.ocjtech.us/${{ github.repository_owner }}
-          REPOSITORY: nixos-runner
+          REGISTRY: git.ocjtech.us
+          REPOSITORY: ${{ github.repository_owner }}/nixos-runner
           USERNAME: ${{ github.actor }}
           PASSWORD: ${{ github.token }}