Bump fastify from 3.18.0 to 5.7.3 in /example/fastify-pov

Bumps [fastify](https://github.com/fastify/fastify) from 3.18.0 to 5.7.3.
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](fastify/fastify@v3.18.0...v5.7.3)

---
updated-dependencies:
- dependency-name: fastify
  dependency-version: 5.7.3
  dependency-type: direct:production
...

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

Author: dependabot[bot]

example/fastify-pov/package.json

@@ -7,7 +7,7 @@
     "start": "node index.js"
   },
   "dependencies": {
-    "fastify": "3.18.0",
+    "fastify": "5.7.3",
     "point-of-view": "4.15.0",
     "pug": "3.0.3",
     "i18next": "20.3.2",