Bump semver from 5.6.0 to 6.3.0 in /frontend

Bumps [semver](https://github.com/npm/node-semver) from 5.6.0 to 6.3.0.
- [Release notes](https://github.com/npm/node-semver/releases)
- [Changelog](https://github.com/npm/node-semver/blob/master/CHANGELOG.md)
- [Commits](npm/node-semver@v5.6.0...v6.3.0)

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

Author: dependabot-preview[bot]

frontend/package-lock.json

@@ -49,7 +49,7 @@
     "postcss-loader": "^3.0.0",
     "pug": "^2.0.4",
     "rimraf": "^2.6.3",
-    "semver": "^5.6.0",
+    "semver": "^6.3.0",
     "shelljs": "^0.8.3",
     "stylus": "^0.54.7",
     "stylus-loader": "^3.0.2",