OAuth2 token_type is case insensitive
Reading the RFC 6749, the token_type value is case insensitive:
https://tools.ietf.org/html/rfc6749#section-5.1
token_type REQUIRED. The type of the token issued as described in Section 7.1. Value is case insensitive.
Our implementation in OpenID Connect only accepts "Bearer" value, case sensitive. It can breaks compatibility with some providers, like ORCID.