build(deps): bump dotenv from 16.6.1 to 17.3.1 in /backend (#190)

Bumps [dotenv](https://github.com/motdotla/dotenv) from 16.6.1 to 17.3.1.
- [Changelog](https://github.com/motdotla/dotenv/blob/master/CHANGELOG.md)
- [Commits](https://github.com/motdotla/dotenv/compare/v16.6.1...v17.3.1)

---
updated-dependencies:
- dependency-name: dotenv
  dependency-version: 17.3.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

backend/package.json

@@ -27,7 +27,7 @@
     "@fastify/static": "^9.0.0",
     "@libsql/client": "^0.17.0",
     "argon2": "^0.44.0",
-    "dotenv": "^16.4.5",
+    "dotenv": "^17.3.1",
     "drizzle-orm": "^0.45.1",
     "fastify": "^5.7.4",
     "nodemailer": "^8.0.1",