Bump mysqlclient from 1.3.12 to 1.3.13
Bump mysqlclient from 1.3.12 to 1.3.13

Bumps [mysqlclient](https://github.com/PyMySQL/mysqlclient-python) from 1.3.12 to 1.3.13.
- [Release notes](https://github.com/PyMySQL/mysqlclient-python/releases)
- [Changelog](https://github.com/PyMySQL/mysqlclient-python/blob/master/HISTORY.rst)
- [Commits](https://github.com/PyMySQL/mysqlclient-python/compare/1.3.12...1.3.13)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
praekeltfoundation/debian-wheel-mirror