travis: added PHP 7.4

dg · dg · commit d93ef446836a · 2019-11-19T19:38:13.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -5,6 +5,7 @@ php:
     - 7.1
     - 7.2
     - 7.3
+    - 7.4
 
 services:
     - memcached
