Bump grunt-webpack from 3.1.3 to 4.0.2 (#209)

Bumps [grunt-webpack](https://github.com/webpack-contrib/grunt-webpack) from 3.1.3 to 4.0.2.
- [Release notes](https://github.com/webpack-contrib/grunt-webpack/releases)
- [Commits](webpack-contrib/grunt-webpack@v3.1.3...v4.0.2)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

package.json

@@ -57,7 +57,7 @@
     "grunt-contrib-connect": "^3.0.0",
     "grunt-contrib-watch": "^1.0.0",
     "grunt-saucelabs": "^9.0.1",
-    "grunt-webpack": "^3.1.3",
+    "grunt-webpack": "^4.0.2",
     "jest": "^26.0.1",
     "jsdom": "^16.2.2",
     "minimist": "^1.2.5",