Add mention of MariaDB support

[robertsilen]

Hello, thank you for your great project that I've heard good things about :) I took a look at your integration options, and noticed MariaDB is not mentioned alongside on in addition to MySQL at https://next.jitsu.com/integrations/destinations and https://docs.jitsu.com/category/warehouses

As Community Advocate from MariaDB Foundation, I'm reaching out to projects regarding Improving MariaDB support and compatibility - as per my blog about it.

What are your thoughts - would it make sense to change "MySQL" to be "MariaDB / MySQL" in the docs? What is the right repo and file to make a PR for you? Anything else you would like me to take into account like CI testing? (though I didn't see any testing for mysql currently)

[github-actions]

This issue is stale because it has been open for 60 days with no activity.