Major dependency upgrade to PyMySQL v1.2.3

[rolandwalker]

Description

PyMySQL v1.2.0 was a breaking update which was avoided for some time.

The defaults for ping() have changed such that reconnect is False, and reconnect=True is also deprecated with a user-visible warning.

The defaults for SSL support on connect() have also changed: SSL mode is the default, and ssl_disabled must be set if SSL is not wanted.

Changes

• Remove all reconnect parameters to ping().
• Remove reconnect=True pass for mycli's reconnect(), which may never have been useful anyway.
• Add support for the ssl_disabled kwarg to PyMySQL's connect().
• Add a retry for PyMySQL's connect() on SSL failure with ssl_mode of auto.
• Import ssl as ssllib in sqlexecute.py, since there is also a variable with the name ssl.

Each value of --ssl-mode on the client has been tested using a MySQL server both with and without SSL support. For the second case, a MySQL 8 server was run with --tls-version=''. On the client, the ability to connect under each combination was checked, along with consulting the output of /status.

The behavior of the /connect command in various situations is more difficult to verify, but since we only removed the second of three passes to the reconnect behavior, we can be reasonably confident that the overall behavior is still good.

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .