chore(release): set v1.12.0 release date to 2026-11-12 (DX-31560)

The v1.12.0 changelog entry carried the date the feature merged (28 Oct), which now
sits above a Snyk release dated 2 Nov. Set the date to the release date. No
version change: v1.12.0 is already the version in the repo and is not yet released.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Author: reeshika-h

CHANGELOG.md

@@ -4,7 +4,7 @@
 ---
 ## v1.12.0
 
-#### Date: 28 October 2026
+#### Date: 12 November 2026
 
 - Branch create: optional `branch.publish_config.environments` (environment names, not UIDs) clones only the listed environments. `[]` clones none; omitting `publish_config` clones all environments, as before. The list is sent unchanged; an unknown name returns the API's 422 response with its body unchanged and no branch is created.
 - Tests: unit tests for the branch create body with and without the environment list and for a mocked 422. Sanity integration tests for create with two names, `[]`, an unknown name and a mix (not run here).