Add php 7.2 and 7.3 and remove 7.0

.travis.yml

@@ -7,8 +7,9 @@ services:
 sudo: required
 
 php:
-  - 7.0
   - 7.1
+  - 7.2
+  - 7.3
 
 env:
   - BASE_URL="http://127.0.0.1:8080"