config: update pr template warning (vuejs#316)

* config: update pr template warning

* config: use h2 for additional emphasis

Author: bencodezen

.github/pull_request_template.md

@@ -1,7 +1,9 @@
-## Note
+# ⚠️⚠️⚠️ DISCLAIMER ⚠️⚠️⚠️:
 
-Thanks for your interest in submitting a PR! At this time, because the docs are in beta, the team is currently in the midst of changes and we are not ready for additional contributions yet.
+Thanks for your interest in submitting a PR! At this time, because the docs are in beta, the team is currently in the midst of changes. As a result, **we are not ready for additional contributions yet**.
 
-To bring your issue to the team's attention though, we would recommend [creating an issue](https://github.com/vuejs/docs-next/issues/new) and we'll get to it when we can.
+## How can I provide feedback?
+
+To be respectful of your time and ideas, **please [create an issue](https://github.com/vuejs/docs-next/issues/new) instead of a pull request**. Otherwise, we will have to simply close your pull request at this time.
 
 Thanks for your understanding!