add_filter( 'script_loader_tag', 'my_scripts_modifier', 10, 3 );
function my_scripts_modifier( $tag, $handle, $src ) {
    if ( 'fontawesome' === $handle ) {
        return '<script src="' . $src . '" type="text/javascript" integrity="sha384-DJ25uNYET2XCl5ZF++U8eNxPWqcKohUUBUpKGlNLMchM7q4Wjg2CUpjHLaL8yYPH"></script>' . "n";
    }
    return $tag;
}