MariaDB is deprecating tx_isolation in 11.1.1

Problem/Motivation

MariaDB is deprecating tx_isolation in 11.1.1 - see https://mariadb.com/kb/en/mariadb-11-1-1-release-notes/ - in favour of transaction_isolation like MySQL 8. Older versions don't support the new name though.

Steps to reproduce

Proposed resolution

Add a MariaDB version condition to use one or the other in the core database driver.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet