Merge pull request #1830 from spotify/dependabot/npm_and_yarn/helmet-4.0.0

chore(deps): bump helmet from 3.23.2 to 4.0.0

packages/backend-common/package.json

@@ -38,7 +38,7 @@
     "cors": "^2.8.5",
     "express": "^4.17.1",
     "express-promise-router": "^3.0.3",
-    "helmet": "^3.22.0",
+    "helmet": "^4.0.0",
     "morgan": "^1.10.0",
     "stoppable": "^1.1.0",
     "winston": "^3.2.1"