Update copyright statements to 2020

LICENSE.md

 # zlib license
 
-Copyright © 2011-2019 Hugo Locurcio and contributors
+Copyright © 2011-2020 Hugo Locurcio and contributors
 
 **This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software.**
 

README.md

@@ -66,7 +66,7 @@ versions than 5.0.0 will generally not be fixed.
 
 ## License
 
-Copyright © 2011-2019 Hugo Locurcio and contributors
+Copyright © 2011-2020 Hugo Locurcio and contributors
 
 - More Ores code is licensed under the zlib license, see
   [`LICENSE.md`](LICENSE.md) for details.

init.lua

@@ -3,7 +3,7 @@
 ** More Ores **
 By Calinou, with the help of Nore.
 
-Copyright © 2011-2019 Hugo Locurcio and contributors.
+Copyright © 2011-2020 Hugo Locurcio and contributors.
 Licensed under the zlib license. See LICENSE.md for more information.
 =====================================================================
 --]]

mg.lua

 --[[
 More Ores: `mg` mod support
 
-Copyright © 2011-2019 Hugo Locurcio and contributors.
+Copyright © 2011-2020 Hugo Locurcio and contributors.
 Licensed under the zlib license. See LICENSE.md for more information.
 --]]