docs: Add README to nuget packges

[sagilio]

close #191

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

:white_check_mark: sagilio
:x: apiscevs
_{You have signed the CLA already but the status is still pending? Let us recheck it.}