Log Message:
Update databases/py-cassandra-driver to 3.10.0

Features
- Add Duration type to cqlengine
- Community PR review: Raise error on primary key update only if its
  value changed
- get_query_trace() contract is ambiguous

Bug Fixes
- Queries using speculative execution policy timeout prematurely
- Fix map where results are not consumed
- Driver fails to encode Duration's with large values
- UDT values are not updated correctly in CQLEngine
- UDT types are not validated in CQLEngine
- to_python is not implemented for types columns.Type and columns.Date
  in CQLEngine
- Clients spin infinitely trying to connect to a host that is drained
- Resulset.get_query_trace returns empty trace sometimes
- Memory grows and doesn't get removed
- Fix RuntimeError caused by change dict size during iteration
- fix ExponentialReconnectionPolicy may throw OverflowError problem
- Avoid using nonexistent prepared statement in ResponseFuture

Other
- Update README
- Test python versions 3.5 and 3.6
- Docs Warning About Prepare "select *"
- Increase Coverage in CqlEngine Test Suite
- Example SSL connection code does not verify server certificates