setup.cfg: Unblock redis>=4.0.2 (#542, #570)

Upstream commit redis/redis-py@d2b2333
that is included with redis-py >=4.0.2 adds method Redis.sentinel_masters
by making class Redis inherit from SentinelCommands, where the related code resides.

Related to issue #542, follow-up to pull request #570

setup.cfg

@@ -38,10 +38,10 @@ packages =
     django_redis.compressors
 install_requires =
     Django>=2.2
-    redis>=3.0.0
+    redis>=3,!=4.0.0,!=4.0.1
 
 [options.extras_require]
-hiredis = redis[hiredis]>=3.0.0
+hiredis = redis[hiredis]>=3,!=4.0.0,!=4.0.1
 
 [coverage:run]
 omit =