Gravity Forms change < input type=submit > form elements to <button>

gf-input-to-button

/**
 * Change GF input type=submit to HTML 5 <button>
 *
 * @param $button
 * @param $form
 * @return mixed|string
 */
function lc_gf_form_submit_button ( $button, $form ){
    $button = str_replace( "input", "button", $button );
    $button = str_replace( "/", "", $button );
    $button .= "{$form['button']['text']}</button>";
    return $button;
}
add_filter( 'gform_submit_button', 'lc_gf_form_submit_button', 10, 5 );