Bump body-parser and express in /react-express-mongodb/backend

Bumps [body-parser](https://github.com/expressjs/body-parser) and [express](https://github.com/expressjs/express). These dependencies needed to be updated together.

Updates `body-parser` from 1.19.0 to 1.20.3
- [Release notes](https://github.com/expressjs/body-parser/releases)
- [Changelog](https://github.com/expressjs/body-parser/blob/master/HISTORY.md)
- [Commits](https://github.com/expressjs/body-parser/compare/1.19.0...1.20.3)

Updates `express` from 4.17.1 to 4.21.2
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/4.21.2/History.md)
- [Commits](https://github.com/expressjs/express/compare/4.17.1...4.21.2)

---
updated-dependencies:
- dependency-name: body-parser
  dependency-version: 1.20.3
  dependency-type: direct:production
- dependency-name: express
  dependency-version: 4.21.2
  dependency-type: direct:production
...

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

react-express-mongodb/backend/package.json

@@ -13,10 +13,10 @@
   "license": "ISC",
   "dependencies": {
     "bcryptjs": "^2.4.3",
-    "body-parser": "^1.18.2",
+    "body-parser": "^1.20.3",
     "cookie-parser": "^1.4.4",
     "cors": "^2.8.4",
-    "express": "^4.17.1",
+    "express": "^4.21.2",
     "lodash": "^4.17.13",
     "mongodb": "^3.0.7",
     "mongoose": "^6.0.9",