ci: test both push and pull_request events

I think we have a bug with pull_request events so...

action.yml

@@ -73,14 +73,6 @@ runs:
       run: |
         . "$GITHUB_ACTION_PATH/utils.sh"
 
-        # If we were triggered by a PR then this is easy
-        if [ "$GITHUB_EVENT_NAME" = "pull_request" ]; then
-                log "Triggered by a pull request with index: $GITHUB_HEAD_REF"
-                log "Expected PR URL: $GITHUB_SERVER_URL/$GITHUB_REPOSITORY/pulls/$GITHUB_HEAD_REF"
-                echo "pr-number=$GITHUB_HEAD_REF" >> "$GIHUB_OUTPUT"
-                exit 0
-        fi
-
         log 'Determine head_ref'
         # For push & tag events it'll bet GITHUB_REF_NAME, for pull_request events it'll be GITHUB_HEAD_REF
         head_ref=${GITHUB_REF_NAME:-$GITHUB_HEAD_REF}