Add missing semicolon.

Thanks to the many reports:
https://github.com/domokit/sky_sdk/pull/13
https://github.com/domokit/sky_sdk/pull/8

TBR=ianh@google.com
diff --git a/sky/sdk/README.md b/sky/sdk/README.md
index 7ff1c58..a72c8fe 100644
--- a/sky/sdk/README.md
+++ b/sky/sdk/README.md
@@ -48,7 +48,7 @@
 ```
 <sky>
 <script>
-import 'package:your_app_name/main.dart'
+import 'package:your_app_name/main.dart';
 
 void main() {
   new HelloWorldApp();