default version

[misilot]

The documentation says for Ubuntu 18.04LTS is 5.7, but I am not seeing anything that overwrite the mysql_minor_version https://github.com/artefactual-labs/ansible-percona/blob/master/defaults/main.yml#L5 in deploy-pub to be 5.7.

For 1.13 should we be using 5.6 or 5.7?

Thanks!