update redis to 8.4.0

Author: alicebob

README.md

@@ -329,7 +329,7 @@ Commands which will probably not be implemented:
 
 ## &c.
 
-Integration tests are run against Redis 7.2.4. The [./integration](./integration/) subdir
+Integration tests are run against Redis 8.4.0. The [./integration](./integration/) subdir
 compares miniredis against a real redis instance.
 
 The Redis 6 RESP3 protocol is supported. If there are problems, please open

integration/get_redis.sh

@@ -2,7 +2,7 @@
 
 set -eu
 
-VERSION=7.2.4
+VERSION=8.4.0
 
 cd "$(dirname "$0")"
 rm -rf ./redis_src/