Add issue template and other fixes

Author: mosuem

.github/ISSUE_TEMPLATE/http_multi_server.md

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

pkgs/http_multi_server/pubspec.yaml

@@ -2,7 +2,7 @@ name: http_multi_server
 version: 3.2.2-wip
 description: >-
   A dart:io HttpServer wrapper that handles requests from multiple servers.
-repository: https://github.com/dart-lang/http_multi_server
+repository: https://github.com/dart-lang/http/tree/master/pkgs/http_multi_server
 
 environment:
   sdk: ^3.2.0