Update main.dart (#282)

diff --git a/example/main.dart b/example/main.dart
index 1cabc5c..7b3eaa9 100644
--- a/example/main.dart
+++ b/example/main.dart
@@ -6,7 +6,7 @@
   // https://developers.google.com/books/docs/overview
   var url = "https://www.googleapis.com/books/v1/volumes?q={http}";
 
-  // Await the http get response, then decode the json-formatted responce.
+  // Await the http get response, then decode the json-formatted response.
   var response = await http.get(url);
   if (response.statusCode == 200) {
     var jsonResponse = convert.jsonDecode(response.body);