Bump express from 4.16.4 to 4.20.0 in /examples/nodejs

Bumps [express](https://github.com/expressjs/express) from 4.16.4 to 4.20.0.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.16.4...4.20.0)

---
updated-dependencies:
- dependency-name: express
  dependency-type: direct:production
...

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

examples/nodejs/package.json

@@ -14,7 +14,7 @@
   },
   "dependencies": {
     "@tensorflow/tfjs-node": "~4.11.0",
-    "express": "4.16.4",
+    "express": "4.20.0",
     "seedrandom": "3.0.5",
     "upscaler": "latest"
   },