How to install mariadb 10.1.20

I have followed the tip that I got from here - How to change MySQL/MariaDB version
But once it got to this point - sudo apt-get purge mysql* mariadb* it shows this in the dashboard ?
Please someone help. I need circle ci to work urgently.

It is highly recommended to ││ take data backup before removing the data directories.││││ Remove data directories ?│││││││└