fix: Add parallel execution to verification tests

Author: weilycoder

.github/workflows/verify.yml

@@ -27,4 +27,4 @@ jobs:
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         GH_PAT: ${{ secrets.GH_PAT }}
-      run: oj-verify all
+      run: oj-verify all -j 2