Switch from unsupported github.com/dgrijalva/jwt-go

[mariash]

dgrijalva/jwt-go#428

From Dependabots :

jwt-go allows attackers to bypass intended access restrictions in situations with []string{} for m["aud"] (which is allowed by the specification). Because the type assertion fails, "" is the value of aud. This is a security problem if the JWT token is presented to a service that lacks its own audience check. There is no patch available and users of jwt-go are advised to migrate to golang-jwt at version 3.2.1