AWS DocumentDB does not support start_after

[dror-g]

Unfortunately, while DocDB v4+ reports its server version as above 4.2, it does not support start_after for log-replication.
Only resume_after is supported as per AWS "docs".

Maybe add a config option docdb: bool and check it in this if clause..

tap-mongodb/tap_mongodb/streams.py

Line 245 in b84a1e0

change_stream_options["start_after"] = {"_data": bookmark}

Thanks and sorry..