Update .travis.yml

Machy8 · web-flow · commit 3e939ddb8df4 · 2019-04-21T16:42:42.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -3,6 +3,7 @@ language: php
 php:
     - 7.1
     - 7.2
+    - 7.3
 
 before_install:
     - composer self-update
