build(deps-dev): update @types/express requirement to ~4.16.0 (#1033)

Updates the requirements on [@types/express](https://github.com/DefinitelyTyped/DefinitelyTyped) to permit the latest version.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits)

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

packages/stryker-karma-runner/package.json

@@ -34,7 +34,7 @@
     "stryker-api": "^0.18.0"
   },
   "devDependencies": {
-    "@types/express": "~4.11.1",
+    "@types/express": "~4.16.0",
     "@types/semver": "~5.5.0",
     "jasmine-core": "~2.4.1",
     "karma": "~2.0.4",