chore: merge 3.9.1 changelog

Signed-off-by: Etienne Millon <me@emillon.org>

Author: emillon

CHANGES.md

@@ -1,14 +1,17 @@
 Unreleased
 ----------
 
+- Add `dune build --dump-gc-stats FILE` argument to dump Garbage Collection
+  stats to a named file. (#8072, @Alizter)
+
+3.9.1 (2023-07-06)
+------------------
+
 - Disable background operations and threaded console on MacOS and other Unixes
   where we rely on fork. (#8100, #8121, fixes #8083, @rgrinberg, @emillon)
 
 - Initialize async IO thread lazily. (#8122, @emillon)
 
-- Add `dune build --dump-gc-stats FILE` argument to dump Garbage Collection
-  stats to a named file. (#8072, @Alizter)
-
 3.9.0 (2023-06-28)
 ------------------