Why is my Bootstrap 5 navbar not displaying the drop down menu on smaller screens?

I am trying to develop a bootstrap 5 theme for the latest WordPress. I am using Navwalker from here: https://github.com/wp-bootstrap/wp-bootstrap-navwalker. My bootstrap Navbar does not dropdown on smaller screens.

Is it not working because I am using Bootstrap 5 and not bootstrap 4?

Here is my code from my header.php file:

nav class=navbar navbar-expand-md navbar-dark bg-dark role=navigation
    div class=container
        !-- Brand and toggle get grouped for better mobile display --
        button class=navbar-toggler type=button data-toggle=collapse data-target=#bs-example-navbar-collapse-1 aria-controls=bs-example-navbar-collapse-1 aria-expanded=false aria-label=?php esc_attr_e( 'Toggle navigation', 'your-theme-slug' ); ?
            span class=navbar-toggler-icon/span
        /button
        a class=navbar-brand href=#Navbar/a
        ?php
        wp_nav_menu( array(
            'theme_location'    = 'primary',
            'depth'             = 2,
            'container'         = 'div',
            'container_class'   = 'collapse navbar-collapse',
            'container_id'      = 'bs-example-navbar-collapse-1',
            'menu_class'        = 'nav navbar-nav',
            'fallback_cb'       = 'WP_Bootstrap_Navwalker::fallback',
            'walker'            = new WP_Bootstrap_Navwalker(),
        ) );
        ?
    /div

/nav

Here is my code from my functions.php file:

function register_navwalker(){
require_once get_template_directory() . '/class-wp-bootstrap-navwalker.php';
}
add_action( 'after_setup_theme', 'register_navwalker' );

/*Navigation Menus*/
register_nav_menus( array(
    'primary' = __( 'Primary Menu', 'bootstrap' ),
    'secondary' = __( 'Secondary Menu', 'bootstrap' )
) );

        

This is my error:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'register_navwalker' not found or invalid function name in C:\Users\apiro\Local Sites\wordpressbootstraptheme\app\public\wp-includes\class-wp-hook.php on line 292

Call Stack

Time    Memory  Function    Location

1 0.0003 413560 {main}( ) ...\index.php:0

2 0.0006 413832 require( 'C:\Users\apiro\Local Sites\wordpressbootstraptheme\app\public\wp-blog-header.php' ) ...\index.php:17

3 0.0006 414376 require_once( 'C:\Users\apiro\Local Sites\wordpressbootstraptheme\app\public\wp-load.php' ) ...\wp-blog-header.php:13

4 0.0007 414816 require_once( 'C:\Users\apiro\Local Sites\wordpressbootstraptheme\app\public\wp-config.php' ) ...\wp-load.php:37

5 0.0007 419496 require_once( 'C:\Users\apiro\Local Sites\wordpressbootstraptheme\app\public\wp-settings.php' ) ...\wp-config.php:79

6 0.0325 2624792 do_action( ) ...\wp-settings.php:538

7 0.0325 2625168 WP_Hook-do_action( ) ...\plugin.php:484

8 0.0325 2625168 WP_Hook-apply_filters( ) ...\class-wp-hook.php:316