Updated Release Notes for 3.1.0

Author: sky333999

RELEASE_NOTES

@@ -1,3 +1,12 @@
+========================================================================
+Amazon CloudWatch Agent Operator v3.1.0 (2025-06-24)
+========================================================================
+Enhancements:
+* Upgrade K8s dependencies to support DRA with K8s 1.33
+* Implement mTLS resources and configuration for Target Allocator server
+* Support security context config with DCGM
+* Add support for UpdateStrategy when collector mode is Deployment
+
 ========================================================================
 Amazon CloudWatch Agent Operator v3.0.1 (2025-05-23)
 ========================================================================