For func (t *JSONWebToken) Claims..., allow passing in options for the json decoder?

[aaomidi]

For example, if I want to parse all the claims into map[string]any for easier looping over them, I might want the JSON decoder to use the following option: https://pkg.go.dev/encoding/json#Decoder.UseNumber

Alternatively, maybe something that can allow the user to specify what JSON decoder to use can also work. Whatever (if any) the preference is I can send in a PR for it.

[mcpherrinm]

I don't think we should make any JSON changes until at least encoding/json/v2 comes out and we have a plan to de-fork our internal JSON decoder.

JSON decoding is security-sensitive in JOSE, so I don't think it will be generally safe to accept decoder options or allow user-specified decoding.