Allow audience & issuer to be specified

[Mongey]

👋 Hey,

When decoding a JWT, I need to specify an audience and issuer.
Currently I get

Wrong token: Invalid audience

Looking at the code there's no way to pass in the intended audience or issuer.

with jose I would do

decoded = jwt.decode(token, public_key, algorithms=[alg], audience=aud, issuer=issuer)

[JoshuaMathias]

In my opinion this is a serious disadvantage of this library and the only one stopping me from getting it to work. I'd recommend allowing passing arbitrary parameters to the init method of JwtAccessBearer that can be used by jose's decode method.

[JoshuaMathias]

I added fixes for this and other payload-related issues: #26
Edit: To avoid waiting, this is now found on pip: https://pypi.org/project/fastapi-jwt-extended/1.0.0/