Update PR template to request everyone write release notes. (#3456)

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,18 +1,6 @@
 <!-- AUTOCHANGELOG for Downstream PRs.
 
-EXTERNAL CONTRIBUTORS: Ignore please - your reviewer will handle.
-
-INTERNAL CONTRIBUTORS AND REVIEWERS: See .ci/RELEASE_NOTES_GUIDE.md
-for writing good release notes.
-
-NO CHANGELOG NOTE: Please add "changelog: no-release-note" label to this PR.
-
-Otherwise, fill the template out (replace the heading).
-You can add more release notes if you want more than one CHANGELOG entry for
-this PR, but make sure not to indent notes and to leave newlines between
-code blocks for Markdown's sake.
-
-For Terraform PRs, we use the following "release-note:" headings
+Please select one of the following "release-note:" headings:
     - release-note:enhancement
     - release-note:bug
     - release-note:note
@@ -21,6 +9,13 @@ For Terraform PRs, we use the following "release-note:" headings
     - release-note:deprecation
     - release-note:breaking-change
     - release-note:none
+    
+Unless you choose release-note:none, please add a release note.
+
+See .ci/RELEASE_NOTES_GUIDE.md for writing good release notes.
+
+You can add more release note blocks if you want more than one CHANGELOG
+entry for this PR.
 -->
 
 **Release Note Template for Downstream PRs (will be copied)**