v5.3.0
Matches the v5.3.0 release at the following nuget links:
https://www.nuget.org/packages/polly/
https://www.nuget.org/packages/Polly-Signed/
https://www.nuget.org/packages/Polly.Net40Async/
https://www.nuget.org/packages/Polly.Net40Async-Signed/