Level.StoreAsEnum is broken

[h0gh]

In the recent changes to support custom column names, it seems the support for storing Level as an enum was broken. (See commit cdd7999 changes to /src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/MSSqlServerSink.cs)

I believe this can be fixed by changing the value of the MaxLength property from 0 to -1 when StoreAsEnum is true, as a value of 0 causes ADO.Net to barf with an exception about non-string datatypes and non-negative MaxLength not being supported. (How's that for triple-negation!)

The functionality works in version 4.0.0 of the Nuget package, but not in version 4.1.0

Thanks in advance!

[colin-young]

Whoops. Fixed, and updated the tests to cover that case.

Good catch. Thanks!