Support `JsonPropertyNameAttribute` on Enum Deserialization

[hughesjs]

This one, again, might be a bit niche or might not be wanted. However, I often find I want to deserialise a string to an enum using a custom value through an attribute, like:

[EnumMember(Value = "Pld Frag Deb")]
PayloadFragmentationDebris,

As it stands, the simple Enum.Parse() used in EnumConverter doesn't (AFAICT) support this

[hughesjs]

#33 was reverted. As was #34, so this is now reopened, as the solution proposed in this PR would require a .NET 6 upgrade.