File Release Notes and Changelog

Build infrastructure updates, compatibility fixes and new features

* Support build with ocaml/msvc and ocaml/mingw (Dmitry Grebeniuk)
* Update build tools (Dmitry Grebeniuk)
* OCaml 3.12 compatibility
* Mysql.Prepared: documentation comments
* Mysql.Prepared.result_metadata (Hezekiah M. Carty)
* Mysql.quick_connect: optional unix socket path
* Mysql.quick_connect: optional connection options