Include new MySQL error code 4031 for MySQL disconnect check
Added disconnect code for MySQL error 4031, introduced in MySQL >= 8.0.24,
indicating connection idle timeout exceeded. In particular this repairs an
issue where pre-ping could not reconnect on a timed-out connection. Pull
request courtesy valievkarim.
Fixes: #8036
Closes: #8037
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/8037
Pull-request-sha:
7ab605c2d25c3cd83af41e3250c97c623220cc7a
Change-Id: I21249c9d8acb305ac43ce61b90b41daf7fabdfe8