chore(deps): bump mongoose from 5.13.14 to 6.1.8

Bumps [mongoose](https://github.com/Automattic/mongoose) from 5.13.14 to 6.1.8.
- [Release notes](https://github.com/Automattic/mongoose/releases)
- [Changelog](https://github.com/Automattic/mongoose/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Automattic/mongoose/compare/5.13.14...6.1.8)

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

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

packages/backend/package.json

@@ -70,7 +70,7 @@
     "jszip": "3.7.1",
     "mdast-util-to-string": "2",
     "mocha": "^8.3.2",
-    "mongoose": "^5.12.13",
+    "mongoose": "^6.1.8",
     "mongoose-bcrypt": "^1.8.1",
     "mongoose-encryption": "^2.1.0",
     "nodemailer": "6.7.2",