Copyright timespan needs update about nelua-lang

[edubart]

I've updated the copyright year in 58a189d using your suggestion, but with a minimum year (in case the system clock is skewed).

is it really necessary to have a copyright timespan?

I think that according to some law, a copyright has life time that eventually ends, it does not hold forever. Imagine we are thousands years in the future and someone wants to use this very old code, since the copyright may have ended centuries ago, the code will be in public domain and the copyright will have no meaning anymore. I think that to hold copyright forever, we have to effectively keep updating the copyright year forever. I am not sure if it works really this way, but that is what I've always assumed.

[stefanos82]

I have completely forgot about the legal obstacles various countries put on us developers.

Thank you for reminding me that!

[Andre-LA]

The Godot developers uses "present" on the lifespan, like: "Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md)"

https://github.com/godotengine/godot/blob/37d51d2cb7f6e47bef8329887e9e1740a914dc4e/core/math/a_star.cpp#L8