Add .htaccess file to exclusion list in Update.md

doc/Update.md

@@ -11,6 +11,8 @@ If you installed Friendica in the ``path/to/friendica`` folder:
 2. Copy  the following items from ``path/to/friendica`` to ``path/to/friendica_new``:
    * ``config/local.config.php``
    * ``proxy/``
+   * ``.htaccess`` if using Apache web server
+
     The following items only need to be copied if they are located inside your friendica path:
    * your storage folder as set in **Admin -> Site -> File Upload -> Storage base path** 
    * your item cache as set in **Admin -> Site -> Performance -> Path to item cache**