Adding Google Maps API key to code

I created a new map and it does not work because it needs a Google Maps API key.

I generated one and I wrote code to add it to the call to //maps.google.com/maps/api/js.

add_action('wp_footer', 'sm_add_gmaps_api_key', 1);
function sm_add_gmaps_api_key() {
    wp_deregister_script('google-maps-api');

    $gmaps_api_key = 'Insert Your API Key Here';
    wp_register_script('google-maps-api', '//maps.google.com/maps/api/js?key='.$gmaps_api_key, false, null, true);
}

I have a suggestion to allow users enter an API key without using a new options page: add a new parameter to the shortcode!

https://wordpress.org/plugins/simple-map/