update copyright year (#15977)

Contributed by Daniel Felix.

git-svn-id: http://svn.redmine.org/redmine/trunk@12736 e93f8b46-1217-0410-a6f0-8f06a7374b81
German translation updated by Daniel Felix (#15980)

git-svn-id: http://svn.redmine.org/redmine/trunk@12737 e93f8b46-1217-0410-a6f0-8f06a7374b81
fix r12737 de.yml alphabetical order

git-svn-id: http://svn.redmine.org/redmine/trunk@12738 e93f8b46-1217-0410-a6f0-8f06a7374b81