Release v3.1.0 for Spark 3.4 and up

The first version with support for Spark 3.
Data throughput boost to 10..20M byte/s per Greenplum segment.
Sub-second latency in the micro-batch streaming mode.

Release v2.1.0 for Spark 2.4.x

Major bug fixes and a lot of new functionality - see README

v2.0.0

For Spark v2.*
Major bug fixes, GPFDist protocol emulation in scala.