laravel使用jwt做小程序认证，不使用默认的password字段

我在做小程序登录状态认证，小程序登录前端已经发送code给我，向微信认证过了，所以我觉得已经不需要password了。

我用的是tymon/jwt-auth，好像默认必须要使用password做验证，如果只是改名的话，就简单了,可去掉password这个字段的话，貌似只能在源码里做改动了

各位老哥，有办法在不改动源码的情况下 ，去掉password字段做小程序登录验证吗？

对了，我还用了多表验证隔离，现在代码是这样的

user.php

<?php
namespace App\Model;

/**
 * 店铺模型，店铺登录模型
 */
use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Tymon\JWTAuth\Contracts\JWTSubject;

class Shop extends Authenticatable implements JWTSubject
{
    use Notifiable;

    /**
     * 表名称
     * @var string
     */
    protected $table = 'shop';
    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        // 'username', 'email', 'password',
        'username' , 'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];

    /**
     * 获取会储存到 jwt 声明中的标识
     * @return mixed
     */
    public function getJWTIdentifier()
    {
        return $this->getKey();
    }

    /**
     * 返回包含要添加到 jwt 声明中的自定义键值对数组
     * @return array
     */
    public function getJWTCustomClaims()
    {
        return ['role' => 'shopadmin'];
    }
}

login.php

<?php

namespace App\Http\Controllers\ShopAdmin;

use Illuminate\Support\Facades\Auth;
use Illuminate\Http\Request;
use App\Http\Controllers\Controller;
use Illuminate\Http\JsonResponse;
use Tymon\JWTAuth\Facades\JWTAuth;
use Illuminate\Support\Facades\Validator;

class LoginController extends Controller
{

    function __construct( )
    {
        $this->middleware('auth:shopadmin', ['except' => ['login']]);
    }

    public function login()
    {

        $credentials = request(['username', 'password']);
        $token = auth('shopadmin')->attempt($credentials);
        if ( !$token ) {
            return $this->fail( 50003 , '账号或者密码错误！' );
        }

        return $this->success( $this->respondWithToken($token) );
    }

    public function me()
    {
        return response()->json(auth('shopadmin')->user());
    }

    public function logout()
    {
        auth('shopadmin')->logout();
        return $this->success( '成功退出登录！Successfully logged out！' );
    }

    public function refresh()
    {   
        $data = $this->respondWithToken(auth('shopadmin')->refresh());
        return $this->success( $data );
    }

    /**
     * @param $token
     * @return JsonResponse
     */
    protected function respondWithToken($token)
    {
        return response()->json([
            'access_token' => $token,
            'token_type' => 'bearer',
            'expires_in' => auth('shopadmin')->factory()->getTTL() * 1
        ]);
    }

}