Move to BouncyCastle 2.0 when available
OpenIddict.Core now references Portable.BouncyCastle on netstandard2.0, which was necessary to work around the lack of PBKDF2 w/ SHA256 and SHA512 support on netstandard2.0-only platforms (which includes .NET Framework 4.6.1, 4.6.2, 4.7 and 4.7.1).
The "official" BouncyCastle package should be updated to support .NET Standard 2.0 at some point, as part of the 1.9.0 release. Once available, we should replace Portable.BouncyCastle by BouncyCastle.
https://github.com/bcgit/bc-csharp/pull/68
Native .NET Standard 2.0 support is planned for BouncyCastle 2.0: https://github.com/bcgit/bc-csharp/pull/68#issuecomment-947209926
BouncyCastle 2.0 was released earlier today: https://github.com/bcgit/bc-csharp/pull/68#issuecomment-1314922176 :tada: