fsprojects onboarding

[sergey-tihon]

@rspeele First of all, welcome to fsprojects!
I've restored your admin access to the repo.

Can you please:

• Add Maintainers section in the README.md like this one.
• Make the fsprojects nuget account a co-owner on any nuget packages associated with the repo.

[xperiandri]

@rspeele ping. We need to release .NET Standard version