chore: update CHANGELOG release date to 2026-05-22 [skip-runtime-e2e]

Date-only update on the topmost release-line section header to match
the actual release day. No content changes.

## Skip-runtime-e2e justification

Pure documentation change — only CHANGELOG.md is touched. No runtime
binary, SDK, or agent code path changes. No env-var defaults, wire
shape, or feature behavior affected. No runtime feature surface exists
for runtime-e2e to exercise.

Signed-off-by: Saurabh Jain <saurabh.jain@getaxonflow.com>

Author: saurabhjain1592

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to the AxonFlow Java SDK will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [8.1.0] - 2026-05-19 — `X-Client-ID` header on every outbound request + `org_id` in telemetry heartbeat + retry-config doc honesty
+## [8.1.0] - 2026-05-22 — `X-Client-ID` header on every outbound request + `org_id` in telemetry heartbeat + retry-config doc honesty
 
 Companion release to the v9 identity cleanup on the platform. Every
 governed request now carries an `X-Client-ID: <effective_client_id>`