chore: update CI/CD workflow to use internal gitea-runner-on-dsm runner

.gitea/workflows/cicd.yml

@@ -38,7 +38,7 @@ jobs:
     name: Build & Push Docker Image
     needs: lint
     if: github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/v')
-    runs-on: ubuntu-latest
+    runs-on: gitea-runner-on-dsm
     permissions:
       packages: write
       contents: read