Inherit CrateDB's `_ObjectArray` from PostgreSQL's dialect `ARRAY`?

[amotl]

About

Investigate if this is sensible. I think UserDefinedType should only be used as a last resort, other TypeEngine-based mappings provide better usability.

Code

sqlalchemy-cratedb/src/sqlalchemy_cratedb/type/array.py

Lines 99 to 102 in adff60b

	# TODO: Should this be inherited from PostgreSQL's
	# `ARRAY`, in order to improve type checking?
	class _ObjectArray(sqltypes.UserDefinedType):
	cache_ok = True