ci: use mysqlclient in tests

.github/helper/install.sh

@@ -6,7 +6,7 @@ cd ~ || exit
 
 sudo apt update
 sudo apt remove mysql-server mysql-client
-sudo apt install libcups2-dev redis-server mariadb-client
+sudo apt install libcups2-dev redis-server mariadb-client libmariadb-dev
 
 pip install frappe-bench
 

.github/helper/site_config_mariadb.json

@@ -8,6 +8,7 @@
  "mail_login": "test@example.com",
  "mail_password": "test",
  "admin_password": "admin",
+ "use_mysqlclient": 1,
  "root_login": "root",
  "root_password": "root",
  "host_name": "http://test_site:8000",