Laravel 5.6 updates

Travis config update

Removed HHVM script as Laravel no longer support HHVM after releasing 5.3

vendor/symfony/var-dumper/Cloner/Data.php

@@ -165,18 +165,6 @@ class Data implements \ArrayAccess, \Countable, \IteratorAggregate
         return sprintf('%s (count=%d)', $this->getType(), \count($value));
     }
 
-    /**
-     * @return array The raw data structure
-     *
-     * @deprecated since version 3.3. Use array or object access instead.
-     */
-    public function getRawData()
-    {
-        @trigger_error(sprintf('The "%s()" method is deprecated since Symfony 3.3 and will be removed in 4.0. Use the array or object access instead.', __METHOD__));
-
-        return $this->data;
-    }
-
     /**
      * Returns a depth limited clone of $this.
      *