fix IMDS changelog (#3722)

* feature changelog

Author: L-Applin

.changes/next-release/feature-AWSSDKforJavav2-0fca976.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "AWS SDK for Java v2",
+    "contributor": "",
+    "description": "EC2 Instance Metadata Client is now generally available - https://github.com/aws/aws-sdk-java-v2/issues/61"
+}