PHP 7.2 is now the current version, so run tests against it.

petercoles · petercoles · commit 4fd7aaea7c0d · 2018-01-02T16:28:54.000Z
diff --git a/.travis.yml b/.travis.yml
@@ -3,6 +3,7 @@ language: php
 php:
   - 7.0
   - 7.1
+  - 7.2
 
 before_script:
   - composer self-update
