Update JsonWebKey2020 to JsonWebKey

[decentralgabe]

As per https://w3c.github.io/vc-jose-cose/

[peacekeeper]

Makes sense to align with VC specs.

[decentralgabe]

As @msporny mentioned today we can either update the existing context or create a new one.
My guess is we'll probably need a new context for 1.1 anyway, so we could have this issue follow that one.
Alternatively, we could create a new examples context and solve this quicker.

I'm fine with either path.

[iherman]

My guess is we'll probably need a new context for 1.1 anyway

I am not so sure. I would not think we would add new properties for DID Documents (we may not even be allowed to do so), and that would be the only reason to change the context.

[pchampin]

This was discussed during the did meeting on 2024-09-05:
https://www.w3.org/2024/09/05-did-minutes.html#t06