CHANGELOG: update

Signed-off-by: Gyuho Lee <leegyuho@amazon.com>

Author: gyuho

CHANGELOG/CHANGELOG-1.4.md

@@ -4,8 +4,13 @@
 
 See [code changes](https://github.com/aws/aws-k8s-tester/compare/v1.4.1...v1.4.2).
 
+### `ec2`
+
+- Handle [duplicate EC2 key pair creation error](https://github.com/aws/aws-k8s-tester/commit/3dcaaa7c799d2e5fd5b7d42f18533a36fae37178).
+
 ### `eks`
 
+- Handle [duplicate EC2 key pair creation error](https://github.com/aws/aws-k8s-tester/commit/3dcaaa7c799d2e5fd5b7d42f18533a36fae37178).
 - Wait [`AddOnClusterVersionUpgrade.WaitBeforeUpgrade` before running cluster version upgrades](https://github.com/aws/aws-k8s-tester/commit/a254e0df3e10e59adee30851a692d104d173ec9f).
 - Fix [instance state polling in `eks/ng` and `eks/mng`](https://github.com/aws/aws-k8s-tester/commit/7ee2e8c2887d2d61e596cff793c591490f681ac3).