Bump html-webpack-plugin from 4.3.0 to 5.6.0 in /etp-public

Bumps [html-webpack-plugin](https://github.com/jantimon/html-webpack-plugin) from 4.3.0 to 5.6.0.
- [Release notes](https://github.com/jantimon/html-webpack-plugin/releases)
- [Changelog](https://github.com/jantimon/html-webpack-plugin/blob/main/CHANGELOG.md)
- [Commits](jantimon/html-webpack-plugin@v4.3.0...v5.6.0)

---
updated-dependencies:
- dependency-name: html-webpack-plugin
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>