Test against PHP 7.2

Author: danielmadu

.travis.yml

@@ -3,6 +3,7 @@ language: php
 php:
   - 7.0
   - 7.1
+  - 7.2
 
 before_script:
   - travis_retry composer self-update --preview
@@ -16,4 +17,4 @@ before_install:
   - echo "extension = redis.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
 
 after_success:
-  - codecov
+  - codecov