Shared scoped between different updates

[tuscen]

In your current implementation all update handlers share a scope because getUpdates can return more than one update at a time. I think it would be better if every individual update would have it's own scope. It can be achieved by using IServiceScopeFactory and explicitly creating scope for each update inside HandleUpdateAsync.

[tuscen]

This issue is a part of #14 and will be solved together with it.