Update license.md

[TallTed]

• - present is not valid for copyright statements
• firstyear–latestyear construct is a valid construct

[Mitzi-Laszlo]

Do you have a legal reference about the correct way to date an MIT license? Does that mean that every year one has to update all the licences?

[TallTed]

Note that my PR does not "date an MIT license." It corrects the copyright notice statement which is part of the license document.

Numerous references available on the web, including government publications (which tend to be somewhat nationally focused, but are generally for signatories of recent copyright conventions) showing the correct form of copyright notices.

[Mitzi-Laszlo]

Thank you for the link @TallTed

Noticing that these are examples of who it's done otherwise. Wondering if you have any reference saying that "2017 - present" would invalidate the license?

[TallTed]

@Mitzi-Laszlo - I do not believe including - present would invalidate the copyright notice (which, again, is distinct from the license which bears it); - present is basically meaningless in a copyright notice/statement. - present does not have the effect of enumerating any year (unless, possibly, the document on which it is placed is itself dated, so including some definition of present, but this would be determined by the judge, magistrate, etc., during litigation on each and every copyright infringement lawsuit), so it's pointless to include it, even if it leaves the rest of the notice in play; and it's arguably problematic as it may lead people who should be adding a year to the enumerated list to not do so, which would let that declared copyright expire sooner than it otherwise would.

[TallTed]

Conflicts resolved... Again ready to merge.

[Mitzi-Laszlo]

Let's get the view of a professional and adapt all the licenses accordingly so that all repos have a uniform approach.