update travis

Author: tas2580

.travis.yml

@@ -5,22 +5,14 @@ language: php
 
 matrix:
   include:
-    - php: 5.4
-      env: DB=mysqli
-    - php: 5.4
-      env: DB=mysql
-    - php: 5.4
-      env: DB=mariadb
-    - php: 5.4
-      env: DB=postgres
     - php: 5.4
       env: DB=sqlite3
     - php: 5.5
-      env: DB=mysqli
+      env: DB=postgres
     - php: 5.6
       env: DB=mysqli
     - php: 7.0
-      env: DB=mysqli
+      env: DB=mariadb
     - php: 7.1
       env: DB=mysqli
   fast_finish: true