README: update MariaDB versions we test against (#404) (#406)

(cherry picked from commit 6f87620)

Co-authored-by: Andrew Klychkov <aklychko@redhat.com>

Author: patchback[bot]

README.md

@@ -71,8 +71,8 @@ Every voice is important and every idea is valuable. If you have something on yo
 
 - mysql 5.7.31
 - mysql 8.0.22
-- mariadb 10.3.34
-- mariadb 10.5.9
+- mariadb 10.3.34 (only collection version >= 3)
+- mariadb 10.8.3 (only collection version >= 3)
 
 ### Database connectors