Bump webpack-merge from 5.1.2 to 5.1.3

Bumps [webpack-merge](https://github.com/survivejs/webpack-merge) from 5.1.2 to 5.1.3.
- [Release notes](https://github.com/survivejs/webpack-merge/releases)
- [Changelog](https://github.com/survivejs/webpack-merge/blob/master/CHANGELOG.md)
- [Commits](survivejs/webpack-merge@v5.1.2...v5.1.3)

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

Author: dependabot[bot]

apps/viewer/package-lock.json

@@ -101,6 +101,6 @@
     "vue-template-compiler": "^2.6.12",
     "webpack": "^4.44.1",
     "webpack-cli": "^3.3.12",
-    "webpack-merge": "^5.1.2"
+    "webpack-merge": "^5.1.3"
   }
 }