Custom action button in Gutenberg editor (post_submitbox_misc_actions – equivalent)

wp_enqueue_script(
    'some-slug',
    '/path/to/script.js',
    array( 'wp-edit-post', 'wp-plugins', 'wp-i18n', 'wp-element' ),
    '0.1'
);

script.js:

var el = wp.element.createElement;
var __ = wp.i18n.__;
var registerPlugin = wp.plugins.registerPlugin;
var PluginPostStatusInfo = wp.editPost.PluginPostStatusInfo;
var TextControl = wp.components.TextControl;

function MyPostStatusInfoPlugin({}) {
    return el(
        PluginPostStatusInfo,
        {
            className: 'my-post-status-info'
        },
        el(
            TextControl,
            {
                name: 'my_edit_summary',
                label: __( 'Edit summary' ),
                help: __( 'Briefly summarise your changes' )
            }
        )
    );
}

registerPlugin( 'my-post-status-info-plugin', {
    render: MyPostStatusInfoPlugin
} );