Support ESM

[ThePlenkov]

Hi! Could you please fix this:

import { CliHelpRenderer } from '@prostojs/cli-help';
         ^^^^^^^^^^^^^^^
SyntaxError: Named export 'CliHelpRenderer' not found. The requested module '@prostojs/cli-help' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from '@prostojs/cli-help';
const { CliHelpRenderer } = pkg;

Thanks!