Bump webpack-node-externals from 2.5.0 to 2.5.1

Bumps [webpack-node-externals](https://github.com/liady/webpack-node-externals) from 2.5.0 to 2.5.1.
- [Release notes](https://github.com/liady/webpack-node-externals/releases)
- [Commits](https://github.com/liady/webpack-node-externals/commits

)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>