Laravel 5.6 updates

Travis config update

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

vendor/phpunit/php-timer/phpunit.xml

@@ -1,13 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/6.0/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/7.0/phpunit.xsd"
          bootstrap="vendor/autoload.php"
          forceCoversAnnotation="true"
          beStrictAboutCoversAnnotation="true"
          beStrictAboutOutputDuringTests="true"
          beStrictAboutTodoAnnotatedTests="true"
          verbose="true">
-    <testsuite>
+    <testsuite name="default">
         <directory suffix="Test.php">tests</directory>
     </testsuite>