Sign assemblies for all target frameworks.

[ptasz3k]

Rationale is here: https://github.com/stephan-tolksdorf/fparsec/issues/53#issuecomment-611474683

We've built our own strongly named .nuget and placed it in our private nuget source, but i think that it would be better if official packages were fully signed too.

[dallinbeutler]

Any chances this will get merged? Judging on commit history it seems @stephan-tolksdorf or whoever maintains FParsec might have gone dark? This would be really nice to have. (running to the same issue mentioned in your comment)

[ptasz3k]

Dunno, since then i've rewritten our parsers in plain c# using ~~pidgin~~ sprache. It's a pity, but certainly easier to maintain.

EDIT: it was sprache, not pidgin :).

[dallinbeutler]

Huh never heard of it, looks neat! I'll have to keep it on my radar! (also, totally excited for Psychonauts 2 haha)

[stephan-tolksdorf]

Thanks for your contribution! Sorry, it took me so long to merge it.