fixup! update the german translation file header

Signed-off-by: Matthias Aßhauer <mha1993@live.de>

po/documentation.de.po

 # German translations for Git Manual Pages.
 # Copyright (C) YEAR Free Software Foundation, Inc.
 # This file is distributed under the same license as the Git package.
-# Fabio Scotoni <fabio@esse.ch>, 2008.
+# Fabio Scotoni <fabio@esse.ch>, 2008
 # Mark Struberg <struberg@yahoo.de>, 2008
-# Jean-Noël Avila <jn.avila@free.fr>, 2019.
+# Jean-Noël Avila <jn.avila@free.fr>, 2019
 # 
 msgid ""
 msgstr ""