Bump bcrypt from 4.0.1 to 4.2.0 in /back

Bumps [bcrypt](https://github.com/pyca/bcrypt) from 4.0.1 to 4.2.0.
- [Changelog](https://github.com/pyca/bcrypt/blob/main/release.py)
- [Commits](pyca/bcrypt@4.0.1...4.2.0)

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

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

back/requirements.txt

@@ -4,7 +4,7 @@ paho-mqtt==1.6.1
 requests==2.31.0
 redis==5.0.0
 flask_cors==4.0.1
-bcrypt==4.0.1
+bcrypt==4.2.0
 google-auth==2.33.0
 python-dateutil==2.8.2
 gevent