accept a customizable cache timeout when create JwtVerifier

[yanglyu520]

The current implementation of func (j *JwtVerifier) New() (*JwtVerifier, error) in JwtVerifier sets a fixed timeout of 5 minutes for the cache. It would be beneficial to enhance the function to accept a customizable timeout length during JwtVerifier creation. This modification allows users to tailor the cache mechanism according to their specific use cases, particularly when fetching JWK keys might experience interruptions for durations exceeding the current default timeout, such as 10 minutes.