add version information to log file

beamerthemeJuelich.sty

 % Latex-Beamer Template Research Centre Juelich
-% version 18.08
+% version 18.12
 % please report any problems to i.kabadshow@fz-juelich.de
 % this version does support pdflatex, xelatex and lualatex
 %
+\ProvidesPackage{beamerthemeJuelich}%
+           [2018/12/14 v18.12
+            Research Centre Juelich Beamer Template]%
 
 \RequirePackage{ifluatex,ifxetex,ifpdf}
 \RequirePackage{etoolbox}