Filter the Gravity Forms button type to change it to a proper button

functions.php

<?php
/*	
 * mytheme_form_submit_button
 *
 * Filter the Gravity Forms button type to change it to a proper button
 */
function mytheme_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", "mytheme_form_submit_button", 10, 2 );