Release 1.0.30

Add custom HttpClient support to BotConfiguration

Introduce a new property `HttpClient` in the `BotConfiguration` class, allowing for a custom `HttpClient` to be set. If not set, a default `HttpClient` will be used.

Update `BotBuilder` to use this custom `HttpClient` when creating an instance of `TelegramBotClient`. If the `HttpClient` is not provided in the `BotConfiguration`, the default behavior remains unchanged.

Include a `using` directive for `System.Net.Http` in `BotConfiguration` to support the new `HttpClient` property.