Add issue template and other fixes

Author: mosuem

.github/ISSUE_TEMPLATE/web_socket_channel.md

@@ -0,0 +1,5 @@
+---
+name: "package:web_socket_channel"
+about: "Create a bug or file a feature request against package:web_socket_channel."
+labels: "package:web_socket_channel"
+---

pkgs/web_socket_channel/CONTRIBUTING.md

@@ -4,7 +4,7 @@ description: >-
   StreamChannel wrappers for WebSockets. Provides a cross-platform
   WebSocketChannel API, a cross-platform implementation of that API that
   communicates over an underlying StreamChannel.
-repository: https://github.com/dart-lang/web_socket_channel
+repository: https://github.com/dart-lang/http/tree/master/pkgs/web_socket_channel
 
 environment:
   sdk: ^3.3.0