Fix code for PHP 5.5.

Author: bgaillard

src/main/php/Gomoob/Filter/DateTimeParserInterface.php

@@ -41,5 +41,5 @@ interface DateTimeParserInterface
      *
      * @throws \InvalidArgumentException if the provided string has not the format expected by the parser.
      */
-    public function parse(string $str): \DateTime;
+    public function parse(/* string */ $str) /* : \DateTime */;
 }

src/main/php/Gomoob/Filter/Parser/FormatDateTimeParser.php

@@ -65,7 +65,7 @@ class FormatDateTimeParser implements DateTimeParserInterface
     /**
      * {@inheritDoc}
      */
-    public function parse(string $str): \DateTime
+    public function parse(/* string */ $str) /* : \DateTime */
     {
         $date = \DateTime::createFromFormat($this->format, $str);