Use union type when it's ready

To reduce the number of overload function and avoid dynamic type like in like in [here](https://github.com/DrSensor/BatchDI/blob/master/Framework/AspNetCore/IServiceCollectionExtensions.cs#L8-L67), it's best to use union type feature like in [Typescript](https://www.typescriptlang.org/docs/handbook/advanced-types.html) when [it's ready](https://github.com/dotnet/csharplang/issues/399).

Using union type open possibility to use `Invoke` instead of `DynamicInvoke` which can cause [performance boost](https://stackoverflow.com/a/12858434/5221998).