ci: don't even try to auto-add PRs to github project

Auto-adding PRs to the Github project is not working because the
github-token is not available there.

Author: regisb

Diff for: .github/workflows/auto-add-to-project.yml

@@ -1,9 +1,6 @@
-name: Auto Add Issues and Pull Requests to Project
+name: Auto Add Issues to Project
 
 on:
-  pull_request:
-    types:
-      - opened
   issues:
     types:
       - opened