[Openid-specs-fapi] Issue #469: Add protocol version and variant identifier (openid/fapi)

[Nat]

New issue 469: Add protocol version and variant identifier
https://bitbucket.org/openid/fapi/issues/469/add-protocol-version-and-variant

Nat Sakimura:

It probably is a good idea to have a parameter to state that the messages involved is for FAPI v.2 Baseline so that appropriate verification can be invoked by the receiver of the message, especially as it is there v.2.