Add changelog

Author: S-Saranya1

.changes/next-release/bugfix-AWSSDKforJavav2-cefa8ba.json

@@ -0,0 +1,6 @@
+{
+    "type": "bugfix",
+    "category": "AWS SDK for Java v2",
+    "contributor": "",
+    "description": "Fixed 407 Proxy Authentication error when preemptiveBasicAuthenticationEnabled is true. Fixes [#5884](https://github.com/aws/aws-sdk-java-v2/issues/5884)."
+}