Official release of 4.0.0

This release maintains compatibility with the recent release of
OnTopic Library 4.0.0, which contains significant changes to the
API as well as new functionality. New projects should use the
new ASP.NET Core 3.1 adapter; this ASP.NET MVC Framework
version, however, will continue to be supported in the near-term
for ASP.NET projects.

Updated version in preparation for next major release.

Establishing initial semantic version at 3.7.0