ckeditor5-dev-env should require webpack (due to ckeditor5-dev-utils)

[pomek]

📝 Provide detailed reproduction steps (if any)

The issue is related to ckeditor/ckeditor5-package-generator#89.

1. Install @ckeditor/ckeditor5-dev-env
2. Use any function exposed by the package, e.g.:

/**
 * @license Copyright (c) 2021-2022, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md.
 */

'use strict';

const { generateChangelogForSinglePackage } = require( '@ckeditor/ckeditor5-dev-env' );

generateChangelogForSinglePackage( {
	skipLinks: true
} );

✔️ Expected result

No error.

❌ Actual result

(node:8327) UnhandledPromiseRejectionWarning: Error: Cannot find module 'webpack'
Require stack:
- /Users/pomek/Projects/cksource/ckeditor5-zenhub-integration/node_modules/@ckeditor/ckeditor5-dev-utils/lib/builds/getdllpluginwebpackconfig.js
- /Users/pomek/Projects/cksource/ckeditor5-zenhub-integration/node_modules/@ckeditor/ckeditor5-dev-utils/lib/builds/index.js
- /Users/pomek/Projects/cksource/ckeditor5-zenhub-integration/node_modules/@ckeditor/ckeditor5-dev-utils/lib/index.js
- /Users/pomek/Projects/cksource/ckeditor5-zenhub-integration/node_modules/@ckeditor/ckeditor5-dev-env/lib/release-tools/tasks/generatechangelogforsinglepackage.js
- /Users/pomek/Projects/cksource/ckeditor5-zenhub-integration/node_modules/@ckeditor/ckeditor5-dev-env/lib/index.js
- /Users/pomek/Projects/cksource/ckeditor5-zenhub-integration/scripts/release/changelog.js

❓ Possible solution

Add the "webpack" dependency to @ckeditor/ckeditor5-dev-env, as ckeditor5-dev-utils defines it as a peer dependency.

[pomek]

https://github.com/ckeditor/ckeditor5-dev/releases/tag/v28.0.4