Bump webpack-cli from 4.8.0 to 4.9.0

Bumps [webpack-cli](https://github.com/webpack/webpack-cli) from 4.8.0 to 4.9.0.
- [Release notes](https://github.com/webpack/webpack-cli/releases)
- [Changelog](https://github.com/webpack/webpack-cli/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack/webpack-cli/compare/webpack-cli@4.8.0...webpack-cli@4.9.0)

---
updated-dependencies:
- dependency-name: webpack-cli
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -50,7 +50,7 @@
     "styled-jsx": "4.0.1",
     "stylis": "3.5.4",
     "uuid": "8.3.2",
-    "webpack-cli": "4.8.0",
+    "webpack-cli": "4.9.0",
     "xterm": "^4.14.1",
     "xterm-addon-fit": "^0.5.0",
     "xterm-addon-ligatures": "^0.5.1",