chore: Update PULL_REQUEST_TEMPLATE.md

Author: marcoscaceres

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,7 +4,7 @@ The following tasks have been completed:
 
  * [ ] Modified Web platform tests (link to pull request)
 
-Implementation commitment:
+Implementation commitment (and no objections):
 
  * [ ] WebKit (https://bugs.webkit.org/show_bug.cgi?id=)
  * [ ] Chromium (https://bugs.chromium.org/p/chromium/issues/detail?id=)