update theme informations

debian/debian-lines/slim.theme

@@ -1,5 +1,5 @@
-# SpaceFun theme for SLIM
-# by Yves-Alexis Perez <corsac@debian.org>
+# Debian-lines theme for SLIM
+# by Yves-Alexis Perez <corsac@debian.org>, Mateusz Łukasik <mati75@linuxmint.pl>
 # using artwork from Valessio S Brito <valessio at debianart.org>
 # inspired from slim theme by Johannes Winkelmann