Allow Header Extraction without AuthScheme

[JEreth]

We used Fiber in a use case where we get a JWT token in a custom header field from an auth platform like this

{
x-custom-jwt: <mytoken>
}

It seems like can not extract this structure via the fiber JWT middleware as it expects a auth scheme and if not given it crops the first character of the key as it expecs <AuthScheme> <Token>.

See:

jwt/jwt.go

Line 39 in 1a9806c

return auth[l+1:], nil

Suggestion: Either we check if AuthScheme is empty or we trim the token and do not crop with +1

[efectn]

Sorry 😅

[JEreth]

I added a PR: #104

[ReneWerner87]

solved with #104