Bump fastify from 2.12.1 to 2.15.1 in /frameworks/TypeScript/nest

Bumps [fastify](https://github.com/fastify/fastify) from 2.12.1 to 2.15.1.
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](https://github.com/fastify/fastify/compare/v2.12.1...v2.15.1)

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

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

frameworks/TypeScript/nest/package.json

@@ -21,7 +21,7 @@
     "@nestjs/platform-fastify": "6.11.11",
     "@nestjs/typeorm": "7.1.5",
     "cache-manager": "3.1.0",
-    "fastify": "2.12.1",
+    "fastify": "2.15.1",
     "fastify-formbody": "3.1.0",
     "handlebars": "4.7.3",
     "hbs": "4.1.0",