Bump redis from 3.5.3 to 4.1.2.

Bumps [redis](https://github.com/redis/redis-py) from 3.5.3 to 4.1.2.
- [Release notes](https://github.com/redis/redis-py/releases)
- [Changelog](https://github.com/redis/redis-py/blob/master/CHANGES)
- [Commits](redis/redis-py@3.5.3...v4.1.2)

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

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

Author: dependabot[bot]

requirements.txt

@@ -3,7 +3,7 @@ numpy==1.19.4
 requests
 flask-login==0.5.0
 face_recognition==1.3.0
-redis==3.5.3
+redis==4.1.2
 Flask_MonitoringDashboard==3.1.0
 Flask==1.1.2
 Werkzeug==2.0.3