Fix merge queue config (#38)

Author: Mr3zee

.github/workflows/validate-pr.yml

@@ -4,10 +4,10 @@ name: Validate PR
 on:
   workflow_dispatch:
   pull_request:
+    types: [enqueued]
 
 jobs:
   validate-pr:
-    if: ${{ github.event_name != 'pull_request' }} # see the link above
     runs-on: ubuntu-latest
     name: Build
     steps: