#127 Nullability issue

Update ServiceRegistrationGeneratorTests.GenerateRegisterSingletonGen…

…eric.verified.txt

Update Injectio.targets

tweak package generation

Merge pull request #81 from loresoft/dependabot/github_actions/action…

…s/setup-dotnet-4

Bump actions/setup-dotnet from 3 to 4

Update Injectio.Tests.csproj

improve tests

Update README.md

Update Injectio.nuspec

support keyed services