Revise changelog for Sentry bundler plugin updates (#948)

* Revise changelog for Sentry bundler plugin updates

Updated changelog to reflect important changes regarding the Sentry bundler plugins moving to the main repository and related PRs. Adjusted section titles and added details about upcoming SDK major release.

* Apply suggestions from code review

Co-authored-by: Lukas Stracke <[email protected]>

* format

release: 5.3.0

release: 5.2.1

release: 5.2.0

release: 5.1.1

release: 5.1.0

release: 5.0.0

release: 4.9.1

release: 4.9.0

cleanup changelog