Pin NETStandard.Library to 1.6.0

[adriangodong]

I'm trying to use this library in AWS Lambda, which can only run .NET Core 1.0. .NET Core 1.0 can only use NETStandard.Library 1.6.0. I believe the netstandard1.3 now defaults to target 1.6.1.

This PR pins the 1.0 compatible version.

[egorikas]

Hi. Thank you for your contribution. But I have some doubt about the pr.
If we open .net standard docs and go to the .NET implementation support section, It'll be clear for us, that .NET Core 1.0 implements .NET Standard from 1.0 to 1.6.
So, I don't think that the reason of your problems is .NET Standard 1.3

[adriangodong]

@egorikas It is confusing and frankly, I have not figured this out yet, but let me try to explain what may be happening:

When netcoreapp1.0 was released, NETStandard.Library 1.6.0 was released together with it. netcoreapp1.0 itself implements netstandard1.6 (and 1.5, 1.4, etc.).

When netcoreapp1.1 was released, NETStandard.Library was updated to 1.6.1. netcoreapp1.1 implements netstandard1.7 (and 1.6, 1.5, etc.).

NETStandard.Library defines the package versions to use. Two versions of a package can differ in implementation but matches the API definition (netstandard). Since netcoreapp1.0 is a runtime target framework, it needs to reference a compatible library version, not just the standard. This makes netcoreapp1.0 incompatible with NETStandard.Library 1.6.1.

I can't find any documentation but I see this happening when referencing this package from a netcoreapp1.0 application. For reference, this is an error that I got when publishing AWS Lambda project with UnixTimeConverter 1.2.0 referenced:

Error: Project is referencing NETStandard.Library version 1.6.1. Max version supported by netcoreapp1.0 is 1.6.0. Error: NETStandard.Library 1.6.1 is used for target framework netcoreapp1.1. Error: Check the following dependencies for versions compatible with netcoreapp1.0: Error:	Amazon.Lambda.APIGatewayEvents : 1.1.0 Error:	Amazon.Lambda.Serialization.Json : 1.1.0 Error:	UnixTimeConverter : 1.2.0 Error:	GitHubHook : 0.0.0 

[egorikas]

@adriangodong Thank you for your explanation. I've merged the pr and I'm publishing new artifacts this evening (in Moscow's time-zone :) )

[adriangodong]

@egorikas Thank you for merging and publishing this!

[egorikas]

@adriangodong You're welcome!