Bump webpack-merge from 5.3.0 to 5.4.0

Bumps [webpack-merge](https://github.com/survivejs/webpack-merge) from 5.3.0 to 5.4.0.
- [Release notes](https://github.com/survivejs/webpack-merge/releases)
- [Changelog](https://github.com/survivejs/webpack-merge/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/survivejs/webpack-merge/compare/v5.3.0...v5.4.0)

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

package.json

@@ -110,7 +110,7 @@
 		"webpack": "^4.44.2",
 		"webpack-cli": "^3.3.12",
 		"webpack-dev-server": "^3.11.0",
-		"webpack-merge": "^5.3.0"
+		"webpack-merge": "^5.4.0"
 	},
 	"jest": {
 		"moduleFileExtensions": [