Workflows: run CI on PR

CI should run on pull request, not pushes to main

Author: danirabbit

.github/workflows/ci.yml

@@ -3,9 +3,11 @@
 name: CI
 
 on:
-  push:
-    branches:
-      - main
+  pull_request:
+     types:
+       - opened
+       - reopened
+       - synchronize
 
 jobs:
   flatpak:
@@ -56,4 +58,4 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Lint
-        run: io.elementary.vala-lint -d .
+        run: io.elementary.vala-lint -d .