Add support for MariaDB 10.4 - Closes #3.

Author: orf

.travis.yml

@@ -66,10 +66,12 @@ env:
 # MariaDB:
 - COMPOSE_APP=mariadb PYTHON_VERSION=3.6 MARIADB_VERSION=10.2
 - COMPOSE_APP=mariadb PYTHON_VERSION=3.6 MARIADB_VERSION=10.3
+- COMPOSE_APP=mariadb PYTHON_VERSION=3.6 MARIADB_VERSION=10.4
 
 - COMPOSE_APP=mariadb PYTHON_VERSION=3.7 MARIADB_VERSION=10.1
 - COMPOSE_APP=mariadb PYTHON_VERSION=3.7 MARIADB_VERSION=10.2
 - COMPOSE_APP=mariadb PYTHON_VERSION=3.7 MARIADB_VERSION=10.3
+- COMPOSE_APP=mariadb PYTHON_VERSION=3.7 MARIADB_VERSION=10.4
 
 # Browsers:
 - COMPOSE_APP=chrome PYTHON_VERSION=3.6