docs: note MariaDB support in README (#13238)

Author: robertsilen

README.md

@@ -203,7 +203,7 @@ Unrestricted (TSU) exception (see the BIS Export Administration Regulations, Sec
 The following provides more details on the included cryptographic software:
 
 * CloudStack makes use of JaSypt cryptographic libraries.
-* CloudStack has a system requirement of MySQL, and uses native database encryption functionality.
+* CloudStack requires a MySQL-compatible database (MariaDB or MySQL), and uses native database encryption functionality.
 * CloudStack makes use of the Bouncy Castle general-purpose encryption library.
 * CloudStack can optionally interact with and control OpenSwan-based VPNs.
 * CloudStack has a dependency on and makes use of JSch - a java SSH2 implementation.