Release 3.1.0

Sqlg 3.1.0 targets TinkerPop 3.7.2

Due to time constraints, Sqlg 3.1.0 has dropped support for features that has poor or no support. If a particular feature is in fact actively used and needed, raise an issue and we'll put it back in.

Sqlg 3.1.0 no longer supports MariaDB and MySql.

Sqlg 3.1.0 no longer supports for gremlin-server. gremlin does not support a schema nor does it have support managing different bulk modes that are transaction scoped. This means that any use of Sqlg via gremlin-server is severely limited and not recommended for production use-cases.