Add keyword placeholder to tramp.el

* lisp/net/tramp.el: Add Version, Package-Requires, Package-Type
and URL keywords.

lisp/net/tramp.el

@@ -7,6 +7,10 @@
 ;; Maintainer: Michael Albinus <michael.albinus@gmx.de>
 ;; Keywords: comm, processes
 ;; Package: tramp
+;; Version: 0
+;; Package-Requires: ()
+;; Package-Type: multi
+;; URL: https://www.gnu.org/software/tramp/
 
 ;; This is a GNU ELPA :core package.  Avoid functionality that is not
 ;; compatible with the version of Emacs recorded in trampver.el.