Add localization file to jquery.validate

Hi Jackky,

You can use the function gettext to make the validation message translatable.
https://docs.metabox.io/validation/#validation-with-jquery-validation-plugin

// This is a part of the meta box settings
'validation' => [
    'rules'  => [
        'field_id' => [
            'required'  => true,
            'minlength' => 7,
            // More rules here
        ],
        // Rules for other fields
    ],
    'messages' => [
        'field_id' => [
            'required'  => __( 'Password is required', 'text-domain' ),
        ],
    ],
],

You can also enqueue more custom JS file with this action hook rwmb_enqueue_scripts. See more here https://github.com/wpmetabox/meta-box/blob/master/inc/validation.php.