Improve I18N Issue (Based on 1.0.2)

After fully localized this great plugin to zh_TW, I found a UI string without I18N code.

inc\class-wpba-setting.php line 58 should be the following.

<script type='text/javascript' src='https://storage.ko-fi.com/cdn/widget/Widget_2.js'></script><script type='text/javascript'>kofiwidget2.init('<?php esc_html_e( 'Tip Me on Ko-fi', 'wp-basic-authentication' ); ?>', '#29abe0', 'J3J6HM43W');kofiwidget2.draw();</script>

Making the donation button localizable may be a good idea.