org.el: Update version keyword to 9.1.12

Thanks to Nicolas for reminding me.

lisp/org.el

@@ -7,7 +7,7 @@
 ;; Maintainer: Carsten Dominik <carsten at orgmode dot org>
 ;; Keywords: outlines, hypermedia, calendar, wp
 ;; Homepage: https://orgmode.org
-;; Version: 9.1.11
+;; Version: 9.1.12
 ;;
 ;; This file is part of GNU Emacs.
 ;;