Incompatible with UWP

In Unity while building for Windows Univeral 10.

Error: type `System.Runtime.Serialization.SerializationInfo` doesn't exist in target framework

Among others, SerializationInfo does not exist in WP8 or WinRT.
There's a need to create a dll for the Editor and another one for UWP probably using .NET core..

Affected:
AWSSDK.Core.dll
AWSSDK.S3.dll
AWSSDK.CognitoIdentity.dll

Start with the AWS SDK for .NET source linked in the issue and investigate how AWSSDK.Core.dll, AWSSDK.S3.dll, and AWSSDK.CognitoIdentity.dll are built for Unity. Check the target-framework references that introduce SerializationInfo and compare the Editor and UWP requirements. Done means a documented, reproducible build or package arrangement that works for both targets.

Written by the indexing model from the issue text.