change timeout to 15 minutes as the github CI is cutting the job after

20 minutes. not sure why

Author: lrvideckis

.github/workflows/programming_team_code_ci.yml

@@ -27,7 +27,7 @@ jobs:
     - name: Run library checker and aizu tests
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      run: oj-verify all --tle 60 --timeout 21600
+      run: oj-verify all --tle 60 --timeout 900
 
   grep_clangformat_cppcheck:
     runs-on: ubuntu-latest