some features and bug fixs

support parse string of token. (#197)

fix: Prevent panic when exp claim is empty or a string (#193)

Oadk/maxrefresh (#185)

fix: add go module support (#180)

custom cookie name (#175)

feat: parse jwt token in url path. (#173)

Check if token expired in MiddlewareFunc (#169)

nil check in refreshHandler + refreshHandler code refactoring (#165)

fix: IdentityHandler arg (#159)

refactor: add identity as key name. (#156)