Use version range for Serilog dependencies

[nbarbettini]

I've been bitten twice by this: #225 (comment)
I agree with the suggestion in #221 that removing references to Serilog entirely is a good direction for a library project to take.

In the meantime, some of the developer pain could be avoided by declaring a version range in the Nuget package.

Instead of

<PackageReference Include = "Serilog.Sinks.Console" Version="3.1.1" /> <!-- Supports any version 3.1.1 or higher -->

I suggest

<PackageReference Include = "Serilog.Sinks.Console" Version="[3.1.*,4)" /> <!-- Supports 3.1.0 or higher, but not 4.x -->

[smasherprog]

Having all of the serilog references is such a poor design choice. please correct this.