Bump webpack-merge from 4.1.1 to 4.1.2

Bumps [webpack-merge](https://github.com/survivejs/webpack-merge) from 4.1.1 to 4.1.2.
- [Release notes](https://github.com/survivejs/webpack-merge/releases)
- [Changelog](https://github.com/survivejs/webpack-merge/blob/master/CHANGELOG.md)
- [Commits](survivejs/webpack-merge@v4.1.1...v4.1.2)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

package-lock.json

@@ -15,7 +15,7 @@
     "prop-types": "^15.6.0",
     "resolve-url-loader": "^2.2.1",
     "sass-loader": "^6.0.6",
-    "webpack-merge": "^4.1.1"
+    "webpack-merge": "^4.1.2"
   },
   "dependencies": {
     "autoprefixer": "7.1.6",