missing changelogs for mozilla#1919 & mozilla#1921

Author: rosahbruno

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 [Full changelog](https://github.com/mozilla/glean.js/compare/v5.0.0...main)
 
+* [#1921](https://github.com/mozilla/glean.js/pull/1921): BUGFIX: Fix issue causing `glean.client.annotation.experimentation_id` metric to not get added in certain pings.
+* [#1919](https://github.com/mozilla/glean.js/pull/1919): Add `glean.page_id` to Glean automatic events.
+
 # v5.0.0 (2024-03-25)
 
 [Full changelog](https://github.com/mozilla/glean.js/compare/v5.0.0-pre.0...v5.0.0)