Actually add results.db

Author: blyxyas

.github/workflows/weekly.yaml

@@ -43,6 +43,7 @@ jobs:
           git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"
           git config --local user.name "github-actions[bot]"
           cp rustc-perf/results.db .
+          git add results.db
           git commit -a -m "Update results.db for `date +%Y-%m-%d`"
       
       - name: Push changes