fix: add timeout to prevent jobs from running indefinitely

Signed-off-by: Anmol Sharma <[email protected]>

.github/workflows/classroom.yml

@@ -10,6 +10,7 @@ permissions:
 jobs:
   run-autograding-tests:
     runs-on: ubuntu-latest
+    timeout-minutes: 10
     if: github.actor != 'github-classroom[bot]'
     steps:
       - name: Checkout code