Upgrade webpack-dev-middleware dependency

[mikegreiling]

I'm submitting a bug report

Webpack version:
4.0.1

Webpack Karma version:
2.0.7

Karma version:
2.0.0

Please tell us about your environment:
OSX 10.13.3

Browser: Chrome 64, Safari 11.0.3

Current behavior:
Currently karma-webpack has webpack-dev-middleware 1.12.0 listed as a dependency. This is two major versions behind the current release (3.0.0).

Despite #301 having added webpack v4.x as a peerDependency, installing this alongside webpack 4.0.1 will still display warnings because webpack-dev-middleware does not list webpack 4.x as a valid peer. yarn check will actually throw an error because of this.

This is the primary roadblock for my project to upgrade to webpack v4. Our CI will not accept anything for which yarn check produces an error.

Expected/desired behavior:

karma-webpack should use webpack-dev-middleware v2.0.6 which has compatibility with webpack v2.2-4.0, or release a new major version that uses webpack-dev-middleware v3.0.0 and drops compatibility with webpack 2 and 3.

• What is the motivation / use case for changing the behavior?

wanting to use webpack 4 without warnings in my console when installing packages

[limonte]

For sweetalert2 the outdated dependency on webpack-dev-middleware possibly causes the "Some of your tests did a full page reload!" issue: sweetalert2/sweetalert2#986

[philipahlberg]

#316 might be related