Got the wrong upstream repo. It's code, not website

Author: rtoy

.github/workflows/sync.yml

@@ -23,7 +23,7 @@ jobs:
           git config user.email "github-actions[bot]@users.noreply.github.com"
           git config user.name "github-actions[bot]"
 
-          git remote add upstream https://git.code.sf.net/p/maxima/website
+          git remote add upstream https://git.code.sf.net/p/maxima/code
           git fetch upstream
 
           # Sync all branches and tags