Add php 7.4 to travis config (#16)

fre5h · web-flow · commit 799fa9726d4d · 2019-12-03T12:56:00.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -6,6 +6,7 @@ php:
     - 7.1
     - 7.2
     - 7.3
+    - 7.4
 
 before_script:
     - composer self-update
