Trigger action on closed PRs

.github/workflows/main.yml

@@ -8,11 +8,13 @@ on:
   push:
     branches: [ master ]
   pull_request:
+    types: [opened, synchronize, reopened, closed]
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
   # This workflow contains a single job called "build"
   test:
+    if: github.event.action != 'closed' || github.event.pull_request.merged
     # The type of runner that the job will run on
     runs-on: ubuntu-latest