Switch from homepage to repository in pubspec  (#86)

diff --git a/pubspec.yaml b/pubspec.yaml
index db8ca05..4bb77d2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,10 +1,9 @@
 name: fixnum
 version: 1.0.1-dev
-
 description: >-
   Library for 32- and 64-bit signed fixed-width integers with consistent
   behavior between native and JS runtimes.
-homepage: https://github.com/dart-lang/fixnum
+repository: https://github.com/dart-lang/fixnum
 
 environment:
   sdk: '>=2.12.0 <3.0.0'