build(deps-dev): bump css-loader in /packages/template/webpack/tmpl
build(deps-dev): bump css-loader in /packages/template/webpack/tmpl

Bumps [css-loader](https://github.com/webpack-contrib/css-loader) from 3.6.0 to 4.2.1.
- [Release notes](https://github.com/webpack-contrib/css-loader/releases)
- [Changelog](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/css-loader/compare/v3.6.0...v4.2.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
electron-userland/electron-forge,electron-userland/electron-forge,electron-userland/electron-forge,electron-userland/electron-forge