element-web camelCase renaming (welcomeUserId -> welcome_user_id)

roles/custom/matrix-client-element/templates/config.json.j2

@@ -26,7 +26,7 @@
 	"room_directory": {
 		"servers": {{ matrix_client_element_room_directory_servers | to_json }}
 	},
-	"welcomeUserId": {{ matrix_client_element_welcome_user_id | to_json }},
+	"welcome_user_id": {{ matrix_client_element_welcome_user_id | to_json }},
 	{% if matrix_client_element_enable_presence_by_hs_url is not none %}
 		"enable_presence_by_hs_url": {{ matrix_client_element_enable_presence_by_hs_url | to_json }},
 	{% endif %}