Fix phpdoc for JsonSchena::setType() (#154)

The type definition in `setType` method can be updated as the property itself accepts `string` too

Author: simivar

src/JsonSchema.php

@@ -648,7 +648,7 @@ public function setEnum($enum)
     /** @codeCoverageIgnoreEnd */
 
     /**
-     * @param array $type
+     * @param array|string $type
      * @return $this
      * @codeCoverageIgnoreStart
      */