Update PHP versions in Travis test matrix.

Author: boonebgorges

.travis.yml

@@ -6,8 +6,9 @@ language: php
 
 # Versions of PHP to test against
 php:
-  - 5.3
-  - 5.4
+  - 5.6
+  - 7.0
+  - 7.1
 
 # Specify versions of WordPress to test against
 # WP_VERSION = WordPress version number (use "master" for SVN trunk)