Gremlin.Net should be strong-name signed

Users that strong-name sign their assemblies currently cannot use our Gremlin.Net NuGet packages as they are not strong-name signed as strong-named assemblies can only reference strong-named assemblies.
I just strong-name signed the pre-GLV version of Gremlin.Net as it was requested by users.

More information about strong-naming: https://docs.microsoft.com/en-us/dotnet/framework/app-domains/strong-named-assemblies