[JAVA] Remove deprecated event-related classes (#515)

* events classes deprecation

Author: rachel-mack

source/upgrade.txt

@@ -241,6 +241,27 @@ This driver version introduces the following breaking changes:
   the error labels included in the ``MongoException`` object that contains the
   ``WriteConcernError``.
 
+- Removes the following classes from the
+  ``com.mongodb.event`` package:
+  
+  - ``ConnectionAddedEvent``
+  - ``ConnectionPoolOpenedEvent``
+  - ``ConnectionRemovedEvent``
+  - ``ClusterListenerAdapter``
+  - ``ConnectionPoolListenerAdapter``
+  - ``ServerListenerAdapter``
+  - ``ServerMonitorListenerAdapter``
+
+  Because of these removals, the following methods were also removed from the
+  ``ConnectionPoolListener`` interface:
+  
+  - ``connectionAdded``
+  - ``connectionPoolOpened``
+  - ``connectionRemoved``
+  
+  For more information about the events package, see the `com.mongodb.event
+  package documentation <{+api+}/apidocs/mongodb-driver-core/com/mongodb/event/package-summary.html>`__
+
 .. _java-breaking-changes-v4.8:
 
 Version 4.8 Breaking Changes