認可リクエストにおける PKCE 利用の強制化

curl -s -X POST .../auth/authorization \
    -u ... \
    -H 'Content-Type: application/json' \
    -d '{"parameters": "redirect_uri=...&response_type=code&client_id=...&scope=..."}'

{
    "resultCode": "A124301",
    "resultMessage": 
      "[A124301] The authorization request does not contain
       'code_challenge' parameter. See RFC 7636 for details.",
    ...
}