Fix error with webpack-dev-server

Hi Webpackers!

This release contains just one bug fix if you're using the webpack-dev-server

• #1031 - changing position of host option for webpack-dev-server - @weaverryan

To upgrade run:

yarn upgrade "@symfony/webpack-encore@^1.6.1"

Changes: v1.6.0..v1.6.1

Documentation: http://symfony.com/doc/current/frontend.html

Happy packing!