Bump webpack from 3.12.0 to 4.47.0 (#1156)

Bumps [webpack](https://github.com/webpack/webpack) from 3.12.0 to 4.47.0.
- [Release notes](https://github.com/webpack/webpack/releases)
- [Commits](webpack/webpack@v3.12.0...v4.47.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -75,7 +75,7 @@
     "style-loader": "^0.23.1",
     "sw-precache-webpack-plugin": "^1.0.0",
     "uglifyjs-webpack-plugin": "^1.2.3",
-    "webpack": "^3.10.0"
+    "webpack": "^4.47.0"
   },
   "devDependencies": {
     "eslint": "^7.10.0",