History of releases and changes in lgdbm

* lgdbm-104	2026-10-08
- use gdbm 1.26
- removed advanced flags in open
- updated README

* lgdbm-103	2023-06-09
- use gdbm 1.23
- gdbm_close and gdbm_sync now return error code

* lgdbm-102	2020-12-30
- use gdbm 1.19
- added gdbm URL in src/Makefile

* lgdbm-101	2019-07-30
- use gdbm 1.18.1

* lgdbm-100	2018-08-06
- first release
- use gdbm 1.16

