Add contribution example for closed pr message (#28)

Marc Navarro · web-flow · commit 3036206bfe11 · 2020-10-08T21:29:12.000+02:00
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -26,3 +26,9 @@ Simulate a pull request has been merged
 ```
 act pull_request -e tests/events/pull_request_merged.json
 ```
+
+Simulate a pull request has been closed without merging
+
+```
+act pull_request -e tests/events/pull_request_closed.json
+```
