Support net6.0; Remove support for obsolete frameworks

[jon-armen]

• Target Frameworks

  • Remove support for net45 (obsolete)
  • Remove support for netcoreapp2.0 (obsolete)
  • Add support for net462
  • Add support for net672
  • Add support for net48
  • Add additional support for netcoreapp3.1 (added to additional Handlers)
  • Add support for net6.0

• AWS SDK

  • Upgrade AWS SDK from v3.3 to v3.7

• Related Issues

  • How about updating Least .NET Framework version to .NET452 #97 Update .net framework version to 4.5.2 #101 .Net SDK release v3.0.0 #102 This will update the frameworks to require 4.6.2 at a minimum since 4.5.2 will be out of support come April 2022

[lupengamzn]

Hi @jon-armen,

Thanks for the contribution and we'll review your PR soon

[srprash]

Hi @jon-armen
I understand the motivation to drop the unsupported frameworks and we should definitely do that.
However, since dropping these frameworks will be breaking change, we should do it as part of v3.0.0 of the SDK. Right now I'm discussing the major version bump strategy with the team and will post an update soon.

Thanks!

[jon-armen]

@srprash , Definitely understandable. I certainly don't mind making contributions to help with the updates once you have a plan. Thank you for the update.