deps: bump bcrypt from 4.0.1 to 4.3.0 in /backend

Bumps [bcrypt](https://github.com/pyca/bcrypt) from 4.0.1 to 4.3.0.
- [Changelog](https://github.com/pyca/bcrypt/blob/main/release.py)
- [Commits](pyca/bcrypt@4.0.1...4.3.0)

---
updated-dependencies:
- dependency-name: bcrypt
  dependency-version: 4.3.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/requirements.txt

@@ -9,7 +9,7 @@ pymongo==4.13.1
 motor==3.7.1
 firebase-admin==6.9.0
 python-dotenv==1.0.0
-bcrypt==4.0.1
+bcrypt==4.3.0
 email-validator==2.2.0
 pytest
 pytest-asyncio