better php version compatibility for travis

Laurent MINGUET · Laurent MINGUET · commit 6129a41309df · 2018-06-15T11:23:08.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,10 +1,10 @@
 language: php
 php:
-  - 5.3
   - 5.4
   - 5.5
   - 5.6
   - 7.0
+  - 7.1
 
 before_script:
   - composer install
