Fixed #34212 -- Made RedisCacheClient.incr() use write connection.

Co-authored-by: Sin-Woo Bang <sinwoobang@gmail.com>

django/core/cache/backends/redis.py

@@ -130,7 +130,7 @@ class RedisCacheClient:
         return bool(client.exists(key))
 
     def incr(self, key, delta):
-        client = self.get_client(key)
+        client = self.get_client(key, write=True)
         if not client.exists(key):
             raise ValueError("Key '%s' not found." % key)
         return client.incr(key, delta)