Add changelog

Author: RanVaknin

.changes/next-release/feature-AmazonDynamoDBEnhancedClient-9637599.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "Amazon DynamoDB Enhanced Client",
+    "contributor": "",
+    "description": "Improved performance by adding a fast path avoiding wrapping of String and Byte types"
+}