gnu: emacs-org-re-reveal: Update to 2.12.2.

gnu: emacs-org-re-reveal: Update to 2.12.2.

[[PGP Signed Part:No public key for 7C7AFFBEFEF2CB25 created at 2020-05-14T11:15:53+0200 using RSA]]
To test this, I made a presentation about guix git workflow in emacs:
https://www.rohleder.de/~mike/guix-workflow/

maybe, its useful for someone.

From 528ccdab63cf399012582450491be6df3d8cc431 Mon Sep 17 00:00:00 2001
From: Michael Rohleder <mike@rohleder.de>
Date: Thu, 14 May 2020 08:16:49 +0000
Subject: [PATCH] gnu: emacs-org-re-reveal: Update to 2.12.2.

* gnu/packages/emacs-xyz.scm (emacs-org-re-reveal): Update to 2.12.2.