Update to Developers: Chromium Issue Tracker migration

Chromium will migrate its issue tracker to Chromium Issue Tracker, powered by Google Issue Tracker, targeting early February 202This change aims to enhance the user experience for the long term. The migration will include all Chromium issues, including issue history and stars. The existing transparency levels to bugs will be maintained. Additional resources, including a walkthrough of the new issue tracker, will be provided before the migration. Existing Monorail issue links will redirect to migrated issues in the new tracker. Post-migration, there will be some differences, but the migration process is designed to be straightforward. If you have questions or concerns, contact issue-tracker-support@chromium.org.