Bump redis from 5.1.1 to 5.2.1 in /requirements

Bumps [redis](https://github.com/redis/redis-py) from 5.1.1 to 5.2.1.
- [Release notes](https://github.com/redis/redis-py/releases)
- [Changelog](https://github.com/redis/redis-py/blob/master/CHANGES)
- [Commits](redis/redis-py@v5.1.1...v5.2.1)

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

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

requirements/base.txt

@@ -7,7 +7,7 @@ argon2-cffi==23.1.0
 # https://github.com/evansd/whitenoise
 whitenoise==6.7.0
 # https://github.com/andymccurdy/redis-py
-redis==5.1.1
+redis==5.2.1
 # https://github.com/redis/hiredis-py
 hiredis==3.0.0
 # https://github.com/psycopg/psycopg2