Support PostgreSQL 13

Support release for PostgreSQL 13.

Support PostgreSQL 12

• Support PostgreSQL 12

• Fix wrong spelling in internal usage of DBMONEY.
  The Informix documentation states that DB_MONEY is the wrong name, instead DBMONEY without the underline is correct.

• Fix handling of BIGSERIAL and variable length character types.
  Since PostgreSQL 12 it is necessary to support short varlena headers again. We can't rely on 4 byte headers anymore (not sure if that was right from the beginning)
  BIGSERIAL types are different from SERIAL8, which was an oversight in the original implementation.
  See commit 9ca46de for more details.

Release 0.5.1

Fixed bugs in this release:

• Call datatype input functions of varlena types with its correct signature (fix by novakka4096)
• Better handling when reading datums from tuple slots. The former code will have problems
  when reading virtual tuples, which this fix corrects. (code by knovak)

Improvements/Code:

• Improve/fix support for older PostgreSQL releases

Support for PostgreSQL 11.

Support PostgreSQL 11.

This release is a support release for the upcoming new PostgreSQL major version.

Users having PostgreSQL 9.3 in production are advised to make sure they rebuild
the Informix FDW when updating from a version earlier than PostgreSQL 9.3.19.

Fix PostgreSQL DATE to Informix DATE datatype conversion

This bugfix release fixes a bug in PostgreSQL DATE to Informix DATE data type conversion routines, which affected DML commands with INSERT or UPDATE.

Support PostgreSQL 9.5

Release 0.3.0 officially supports the new PostgreSQL 9.5 release and fixes various bugs. Users of older version are also encouraged to update, since serious issues with FLOAT/DOUBLE and DATE/DATETIME datatypes are fixed.