Add php 7.4 in travis (#282)

* Add php 7.4 in travis
* Add ignoring error parameter for travis

Travis does not support phpenv config-rm xdebug.ini for php7.4

Author: Big-Shark

.travis.yml

@@ -6,13 +6,14 @@ php:
   - 7.1
   - 7.2
   - 7.3
+  - 7.4
 
 cache:
   directories:
     - $HOME/.composer/cache/files
 
 before_install:
-  - phpenv config-rm xdebug.ini
+  - phpenv config-rm xdebug.ini || echo "Can't disable xDebug"
   - composer self-update
   - composer global require hirak/prestissimo