Update changelog for v9 (#1843)

Author: vmihailenco

CHANGELOG.md

@@ -3,6 +3,13 @@
 > :heart:
 > [**Uptrace.dev** - All-in-one tool to optimize performance and monitor errors & logs](https://uptrace.dev)
 
+## v9 UNRELEASED
+
+- Added support for [RESP3](https://github.com/antirez/RESP3/blob/master/spec.md) protocol.
+- Removed `Pipeline.Close` since there is no real need to explicitly manage pipeline resources.
+  `Pipeline.Discard` is still available if you want to reset commands for some reason.
+- Replaced `*redis.Z` with `redis.Z` since it is small enough to be passed as value.
+
 ## v8.11
 
 - Remove OpenTelemetry metrics.