Only test supported PHP versions

Author: casperbakker

.travis.yml

@@ -1,12 +1,12 @@
 language: php
 
 php:
-  - 5.6
-  - 7.0
-  - hhvm
+  - 7.2
+  - 7.3
+  - 7.4
 
 sudo: false
 
 install: composer install --no-interaction --prefer-source
 
-script: vendor/bin/phpunit
+script: vendor/bin/phpunit