minor #11732 Redis 4.3 is required (weaverryan)

This PR was merged into the 4.3 branch.

Discussion
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Redis 4.3 is required

See symfony/symfony#31872

But also the conversation on symfony/messenger@47d2b91

So, I'm not actually sure if that commit is correct and the docs should be updated, or if that commit is wrong. Opening this up to at least have some placeholder to figure that out.

Commits
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c76afd3 Redis 4.3 is required

messenger.rst

@@ -877,7 +877,7 @@ The Redis transport uses `streams`_ to queue messages.
     # .env
     MESSENGER_TRANSPORT_DSN=redis://localhost:6379/messages
 
-To use the Redis transport, you will need the Redis PHP extension (^4.2) and
+To use the Redis transport, you will need the Redis PHP extension (^4.3) and
 a running Redis server (^5.0).
 
 .. caution::