Homepage: use https (#4)

diff --git a/pubspec.yaml b/pubspec.yaml
index 4f6f238..e491d72 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,7 +1,7 @@
 name: http_multi_server
 version: 2.0.4-dev
 author: "Dart Team <misc@dartlang.org>"
-homepage: http://github.com/dart-lang/http_multi_server
+homepage: https://github.com/dart-lang/http_multi_server
 description:
   A dart:io HttpServer wrapper that handles requests from multiple servers.
 environment: