On child theme function.php you will find below code.

add_action( 'wp_enqueue_scripts', 'FLChildTheme::enqueue_scripts', 1000 );

Change to

// Actions Pickup Version
function enqueue_bb_child_theme_style() {
    wp_enqueue_style( 'fl-child-theme', FL_CHILD_THEME_URL . '/style.css', array(), wp_get_theme()->get('Version') );
 }
 add_action( 'wp_enqueue_scripts', 'enqueue_bb_child_theme_style', 1000 );

Go to your style.css. Now you can update the 'Version: 1.0' and will pick up the version every time you update the file.

Voilà 🙌