build: bump karma-webpack from 2.0.13 to 3.0.0 (#75)

Bumps [karma-webpack](https://github.com/webpack-contrib/karma-webpack) from 2.0.13 to 3.0.0.
- [Release notes](https://github.com/webpack-contrib/karma-webpack/releases)
- [Changelog](https://github.com/webpack-contrib/karma-webpack/blob/master/CHANGELOG.md)
- [Commits](codymikol/karma-webpack@v2.0.13...v3.0.0)

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

package.json

@@ -59,7 +59,7 @@
     "karma-junit-reporter": "^1.2.0",
     "karma-mocha": "^1.3.0",
     "karma-mocha-reporter": "^2.2.5",
-    "karma-webpack": "^2.0.9",
+    "karma-webpack": "^3.0.0",
     "material-components-web": "0.32.0",
     "mocha": "^5.0.1",
     "node-sass": "^4.7.2",