feat(developer): document new date of birth property on the profile

Signed-off-by: Richard Steinmetz <[email protected]>

developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_30.rst

@@ -122,6 +122,7 @@ Added APIs
 - ``OCP\Calendar\Resource\IManager::update`` was added to update all resources from all backends right now.
 - ``OCP\App\IAppManager::BACKEND_CALDAV`` was added to represent the caldav backend dependency for ``isBackendRequired``.
 - ``OCP\App\IAppManager::isBackendRequired`` was added to check if at least one app requires a specific backend (currently only ``caldav``).
+- ``OCP\Accounts\IAccountManager::PROPERTY_BIRTHDATE `` was added to allow users to configure their date of birth in their profiles.
 
 Changed APIs
 ^^^^^^^^^^^^