release v1.2.0

PiperOrigin-RevId: 824484966
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bbec817..a9d9f4b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,7 @@
 
 ## Unreleased
 
-## [1.2.0] - 2025-10-xx
+## [1.2.0] - 2025-10-27
 
 ### SECURITY
  - python: added `Decompressor::can_accept_more_data` method and optional