Update dependency webpack-dev-server to v3.11.1

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
webpack-dev-server	3.11.0 -> 3.11.1

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Release Notes

webpack/webpack-dev-server

### [`v3.11.1`](https://togithub.com/webpack/webpack-dev-server/releases/v3.11.1) [Compare Source](https://togithub.com/webpack/webpack-dev-server/compare/v3.11.0...v3.11.1) ##### [3.11.1](https://togithub.com/webpack/webpack-dev-server/compare/v3.11.0...v3.11.1) (2020-12-29) ##### Bug Fixes - the `open` option works using `webpack serve` without value ([#​2948](https://togithub.com/webpack/webpack-dev-server/issues/2948)) ([4837dc9](https://togithub.com/webpack/webpack-dev-server/commit/4837dc92b944f8b4cdd7d6e3420367cf338e7f75)) - vulnerable deps ([#​2949](https://togithub.com/webpack/webpack-dev-server/issues/2949)) ([78dde50](https://togithub.com/webpack/webpack-dev-server/commit/78dde50f520c8b78de14272a4ae4cee1281bf2e3))

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