Extension for LoggingBuilder

[Ralstlin]

Hi!

Could be possible to add to https://github.com/vtex/SplunkLogger/blob/master/src/SplunkLogger/LoggerFactoryExtensions.cs extensions like:

public static ILoggingBuilder AddTcpSplunk(this ILoggingBuilder builder)
{
   builder.Services.AddSingleton<ILoggerProvider, SplunkTcpLoggerProvider>();
   return builder;
}