README: Updated copyright year
README: Updated copyright year

.. and linked to AUTHORS file

RBE-Avionik/skylines,skylines-project/skylines,Turbo87/skylines,TobiasLohner/SkyLines,Turbo87/skylines,Harry-R/skylines,RBE-Avionik/skylines,Harry-R/skylines,Turbo87/skylines,Harry-R/skylines,skylines-project/skylines,TobiasLohner/SkyLines,shadowoneau/skylines,Turbo87/skylines,shadowoneau/skylines,snip/skylines,RBE-Avionik/skylines,kerel-fs/skylines,snip/skylines,RBE-Avionik/skylines,kerel-fs/skylines,Harry-R/skylines,shadowoneau/skylines,shadowoneau/skylines,TobiasLohner/SkyLines,kerel-fs/skylines,skylines-project/skylines,skylines-project/skylines,snip/skylines