POST for openid/userinfo is not compatible with OIDC

[gregory1g]

SimSwap/code/API_definitions/MobileConnect/MC_ATP.yaml

Line 75 in c317b02

post:

Correct me if I'm wrong, but IDY.24 implements OIDC openid/userinfo API, not juts coincidentally uses the same endpoint.
OIDC describe this endpoint as a GET API. Using POST here is incompatible with OIDC and breaks REST design principles ("POST UserInfo" looks like an update/create API).

[bigludo7]

Link to camaraproject/NumberVerification#35