Merge pull request #6380 from matrix-org/dbkr/new_changelogs

Update PR template for new changelog generation

Author: dbkr

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,3 +1,15 @@
 <!-- Please read https://github.com/matrix-org/matrix-js-sdk/blob/develop/CONTRIBUTING.md before submitting your pull request -->
 
 <!-- Include a Sign-Off as described in https://github.com/matrix-org/matrix-js-sdk/blob/develop/CONTRIBUTING.md#sign-off -->
+
+<!-- To specify text for the changelog entry (otherwise the PR title will be used):
+Notes:
+
+Changes in this project generate changelog entries in element-web by default.
+To suppress this:
+
+element-web notes: none
+
+...or to specify different notes:
+element-web notes: <notes>
+-->