Update JWT library version

[paemuri]

I know this commit leads to huge changes, so I'll understand any kind of opinion or feedback.

Also, thanks for this awesome project! :)

[aldas]

Probably will not happen before v5.

Meanwhile you can use JWTConfig.ParseTokenFunc callback for whatever library and version you choose. Documentation has example for that: https://echo.labstack.com/middleware/jwt/#custom-configuration

import (
"github.com/golang-jwt/jwt/v4"
)

...
...
...

signingKey := []byte("secret")

config := middleware.JWTConfig{
  TokenLookup: "query:token",
  ParseTokenFunc: func(auth string, c echo.Context) (interface{}, error) {
    keyFunc := func(t *jwt.Token) (interface{}, error) {
      if t.Method.Alg() != "HS256" {
        return nil, fmt.Errorf("unexpected jwt signing method=%v", t.Header["alg"])
      }
      return signingKey, nil
    }

    // claims are of type `jwt.MapClaims` when token is created with `jwt.Parse`
    token, err := jwt.Parse(auth, keyFunc)
    if err != nil {
      return nil, err
    }
    if !token.Valid {
      return nil, errors.New("invalid token")
    }
    return token, nil
  },
}

e.Use(middleware.JWTWithConfig(config))