Configure travis to only use php7.1 & php7.2

Author: jimmypuckett

.travis.yml

@@ -1,26 +1,23 @@
 language: php
 
 php:
-  - 5.5.9
-  - 5.5
-  - 5.6
-  - 7.0
   - 7.1
+  - 7.2
 
 env:
   global:
     - setup=basic
 
 matrix:
   include:
-    - php: 7.0
-      env: setup=lowest
-    - php: 7.0
-      env: setup=stable
     - php: 7.1
       env: setup=lowest
     - php: 7.1
       env: setup=stable
+    - php: 7.2
+      env: setup=lowest
+    - php: 7.2
+      env: setup=stable
 
 sudo: false