Run on pull_request

Author: vkucera

.github/workflows/o2-linter.yml

@@ -2,7 +2,7 @@
 # Find issues in O2 code
 name: O2 linter
 
-"on": [pull_request_target, push]
+"on": [pull_request_target, pull_request, push]
 permissions: {}
 env:
   BRANCH_MAIN: master
@@ -20,7 +20,7 @@ jobs:
     steps:
       - name: Set branches
         run: |
-          if [[ "${{ github.event_name }}" == "push" ]]; then
+          if [[ "${{ github.event_name }}" == "push" || "${{ github.event_name }}" == "pull_request" ]]; then
             branch_head="${{ github.ref }}"
             branch_base="origin/${{ env.BRANCH_MAIN }}"
           else