Adding a bootstrap class to a theme

Hi there,
I am using child theme for DevDMBootstrap3 and I am looking for a way to add a class to a <!– <div> –> that has already been defined. That class I am looking to add is the nav-wrapper.

I am wondering if there is a way for me to do this without editing the parent (so I don’t lose out if it gets updated). What I need to edit is the template-top-part-nav.php file (shown below)

<?php if ( has_nav_menu( 'main_menu' ) ) : ?>

<div class="row dmbs-top-menu">
        <nav class="navbar navbar-inverse static-top" role="navigation">
            <div class="container">
                <div class="navbar-header">
                    <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-1-collapse">
                        <span class="sr-only"><?php _e('Toggle navigation','devdmbootstrap3'); ?></span>
                        <span class="icon-bar"></span>
                        <span class="icon-bar"></span>
                        <span class="icon-bar"></span>
                    </button>
                </div>

                <?php
                wp_nav_menu( array(
                        'theme_location'    => 'main_menu',
                        'depth'             => 2,
                        'container'         => 'div',
                        'container_class'   => 'collapse navbar-collapse navbar-1-collapse',
                        'menu_class'        => 'nav navbar-nav',
                        'fallback_cb'       => 'wp_bootstrap_navwalker::fallback',
                        'walker'            => new wp_bootstrap_navwalker())
                );
                ?>
            </div>
        </nav>
    </div>

<?php endif; ?>

The class I need to edit is the very first one, where it says
<div class="row dmbs-top-menu">
I need to make it:
<div class="row dmbs-top-menu nav-wrapper">
However, like I said, I want to do this in the child theme if possible in case there is an update to the theme.