Prepare debian changelog for 4.0.0
Prepare debian changelog for 4.0.0

mike-tr-adamson/cassandra,jrwest/cassandra,tjake/cassandra,belliottsmith/cassandra,mshuler/cassandra,instaclustr/cassandra,pauloricardomg/cassandra,szhou1234/cassandra,belliottsmith/cassandra,driftx/cassandra,thelastpickle/cassandra,jrwest/cassandra,mshuler/cassandra,tjake/cassandra,instaclustr/cassandra,blambov/cassandra,szhou1234/cassandra,blambov/cassandra,instaclustr/cassandra,adelapena/cassandra,mike-tr-adamson/cassandra,thelastpickle/cassandra,apache/cassandra,pauloricardomg/cassandra,apache/cassandra,driftx/cassandra,mike-tr-adamson/cassandra,thelastpickle/cassandra,driftx/cassandra,driftx/cassandra,blambov/cassandra,jrwest/cassandra,szhou1234/cassandra,belliottsmith/cassandra,belliottsmith/cassandra,tjake/cassandra,mshuler/cassandra,adelapena/cassandra,thelastpickle/cassandra,apache/cassandra,tjake/cassandra,pauloricardomg/cassandra,mike-tr-adamson/cassandra,szhou1234/cassandra,jrwest/cassandra,adelapena/cassandra,pauloricardomg/cassandra,instaclustr/cassandra,mshuler/cassandra,adelapena/cassandra,blambov/cassandra,apache/cassandra