[rocketmq-connect-cassandra] CassandraSinkConnector issue recorder

Since the official GSoC hasn't begun yet, I'll put some rocketmq-connect-cassandra sink connector related issue here, and will unroll these when official code begins
- [x] Cassandra datastax driver depends on a netty version conflict with the rocketmq netty dependency.
- [ ] implement "update" in the Cassandra sink task updater, so we can at least export one record to the Cassandra cluster.

Start by locating the Cassandra sink task updater in the rocketmq-connect-cassandra connector and inspect how records are currently exported. Determine the expected update behavior and verify that completion allows at least one record to be exported to a Cassandra cluster.

Written by the indexing model from the issue text.