Fix incorrectly decoding plus symbol to space in paths

Fixes https://github.com/laravel/valet/issues/829

server.php

@@ -63,7 +63,7 @@ function valet_default_site_path($config)
 /**
  * Parse the URI and site / host for the incoming request.
  */
-$uri = urldecode(
+$uri = rawurldecode(
     explode("?", $_SERVER['REQUEST_URI'])[0]
 );