test: check PHP 7.4 compatibility

mle86 · mle86 · commit 39872c50dc09 · 2020-07-05T19:40:44.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -4,6 +4,7 @@ php:
   - '7.1'
   - '7.2'
   - '7.3'
+  - '7.4'
 
 before_install:
   - composer self-update
