fix: ui/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-PBKDF2-10495496
- https://snyk.io/vuln/SNYK-JS-PBKDF2-10495498

Author: snyk-bot

ui/package.json

@@ -73,7 +73,7 @@
     "tslint-react": "^3.4.0",
     "typescript": "^4.0.3",
     "unidiff": "^1.0.2",
-    "webpack": "^4.44.2",
+    "webpack": "^5.0.0",
     "webpack-cli": "^3.3.12",
     "webpack-dev-server": "^3.11.0"
   },