Upgrade to Serilog.Settings.AppSettings v2.1.1 breaks calls to `.ReadFrom.AppSettings()`

[tsimbalar]

I think it is related to the changes from #10 and #12

The following code no longer compiles after upgrading from v2.1.0 to v2.1.1

    public class LogConfig
    {
        static public void Configure()
        {
            var loggerConfiguration = new LoggerConfiguration().ReadFrom.AppSettings();
            Log.Logger = loggerConfiguration.CreateLogger();
        }
    }

Error	CS0121	The call is ambiguous between the following methods or properties: 'AppSettingsLoggerConfigurationExtensions.AppSettings(LoggerSettingsConfiguration, string)' and 'AppSettingsLoggerConfigurationExtensions.AppSettings(LoggerSettingsConfiguration, string, string)'

I guess probably only one of the overloads should have optional params.

[nblumhardt]

D'oh! Swapped a binary-breaking change for a source-breaking one :-(

Thanks for the heads-up, I'll push a fix straight through...

...and after that I'm taking a short holiday from shipping patches :-)

[nblumhardt]

2.1.2 should have it covered.

[tsimbalar]

Confirmed, works like a charm :)