C.I.: Enable manually run tests on PRs

.github/workflows/ci.yml

@@ -3,8 +3,7 @@ run-name: ${{ github.actor }} is testing out GitHub Actions 🚀
 
 on: 
   push:
-  pull_request_target:
-    types: [opened, edited, reopened]
+  workflow_dispatch:
 
 jobs:
   windows: