Add change and example to changelog

CHANGELOG.md

@@ -11,4 +11,17 @@ Each version will have a separate `Breaking Changes` section as well. To describ
 ### Added
 ### Changed
 ### Breaking changes
+* refactor: add custom error struct in elcontracts writer methods by @maximopalopoli in <https://github.com/Layr-Labs/eigensdk-go/pull/482>
+  * The errors now follow this format: `error name (error code) - error description: underlying error`.
+
+    For example, in this code section:
+    ```go
+	receipt, err := w.txMgr.Send(ctx, tx, waitForReceipt)
+	if err != nil {
+		wrappedError := SendError(err)
+		return nil, wrappedError
+	}
+    ```
+    The returned error if err is not nil would be `Send error (5) - Failed to send tx with err *underlying error*`
+
 ### Removed