Add drone test for mariadb

.drone.yml

@@ -91,11 +91,32 @@ steps:
     - push
     - pull_request
 
+- name: test-mariadb-utf8mb4
+  image: golang:1.12
+  depends_on:
+  - test-mysql-utf8mb4
+  environment:
+    GO111MODULE: "on"
+    GOPROXY: "https://goproxy.cn"
+    TEST_MYSQL_HOST: mariadb
+    TEST_MYSQL_CHARSET: utf8mb4
+    TEST_MYSQL_DBNAME: xorm_test
+    TEST_MYSQL_USERNAME: root
+    TEST_MYSQL_PASSWORD:
+  commands:
+  - make test-mysql
+  - TEST_CACHE_ENABLE=true make test-mysql
+  - TEST_QUOTE_POLICY=reserved make test-mysql
+  when:
+    event:
+    - push
+    - pull_request
+
 - name: test-mymysql
   pull: default
   image: golang:1.12
   depends_on:
-    - test-mysql-utf8mb4
+    - test-mariadb-utf8mb4
   environment:
     GO111MODULE: "on"
     GOPROXY: "https://goproxy.cn"
@@ -260,6 +281,18 @@ services:
     - tag
     - pull_request
 
+- name: mariadb
+  pull: default
+  image: mariadb:10.5
+  environment:
+    MYSQL_ALLOW_EMPTY_PASSWORD: yes
+    MYSQL_DATABASE: xorm_test
+  when:
+    event:
+    - push
+    - tag
+    - pull_request
+
 - name: pgsql
   pull: default
   image: postgres:9.5