build(deps): bump @google-cloud/firestore from 6.6.1 to 6.8.0

Bumps [@google-cloud/firestore](https://github.com/googleapis/nodejs-firestore) from 6.6.1 to 6.8.0.
- [Release notes](https://github.com/googleapis/nodejs-firestore/releases)
- [Changelog](https://github.com/googleapis/nodejs-firestore/blob/main/CHANGELOG.md)
- [Commits](googleapis/nodejs-firestore@v6.6.1...v6.8.0)

---
updated-dependencies:
- dependency-name: "@google-cloud/firestore"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

package-lock.json

@@ -16,7 +16,7 @@
     "@fastify/rate-limit": "^8.0.0",
     "@fastify/swagger": "^8.10.0",
     "@fastify/swagger-ui": "^1.3.0",
-    "@google-cloud/firestore": "^6.5.0",
+    "@google-cloud/firestore": "^6.8.0",
     "ajv": "^8.12.0",
     "ajv-formats": "^2.1.0",
     "fastify": "^4.20.0",