Document changelog that grant_type is now required

[dshanske]

In the current living standard, grant_type is required by the authorization endpoint. In the prior version, it was not. This change needs to be documented due the fact it could be a breaking change.

[Zegnat]

I think this is wrong?

Maybe I am missing something, but I think grant_type has always been required. It was response_type that was optional (in the case of response_type=id) and that has been documented as part of the August 9th changes.

Am I misreading something?

[dshanske]

@Zegnat For the token endpoint, but not the authorization endpoint.

[Zegnat]

Ah, found it now @dshanske. Thanks! PR opened with fix.