JsonWebKey2020 Support

[ross-little]

I used the ion-cli to create a new DID based on Ed25519 and it generated the public key in the DID as shown further below. However, the key type generated in the DID is shown as EcdsaSecp256k1VerificationKey2019, but shouldn´t it be of type": "JsonWebKey2020" :

"ops": [ { "operation": "create", "content": { "publicKeys": [ { "id": "key-1", "type": "EcdsaSecp256k1VerificationKey2019", "publicKeyJwk": { "crv": "Ed25519", "x": "adKxi7VVR8p6k__vcAsg_AW9QyUWaQHZYTj7ZNlWbwQ", "kty": "OKP" }, "purposes": [ "authentication", "keyAgreement" ] } ]