6.1 bullet 3: "CONDITIONAL" is not a keyword in RFC2119

[Nat Sakimura]

In 6.1, bullet 3, “CONDITIONAL” appears as if it is a keyword but it is not per RFC2119. Reword it in a way REQUIRED if …

If I understand correctly, it is meant to be

REQUIRED in pre-authorized code flow. OPTIONAL in other cases. The code represents the issuer's authorization for the Wallet to obtain Credentials of a certain type. This code MUST be short-lived and single-use.