Bump Microsoft.AspNetCore.TestHost from 2.2.0 to 3.0.0
Bump Microsoft.AspNetCore.TestHost from 2.2.0 to 3.0.0

Bumps [Microsoft.AspNetCore.TestHost](https://github.com/aspnet/AspNetCore) from 2.2.0 to 3.0.0.
- [Release notes](https://github.com/aspnet/AspNetCore/releases)
- [Changelog](https://github.com/aspnet/AspNetCore/blob/master/docs/CrossRepoBreakingChanges.md)
- [Commits](https://github.com/aspnet/AspNetCore/compare/2.2.0...v3.0.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
FoundatioFx/Foundatio,exceptionless/Foundatio