Fix changelog link

CHANGELOG.md

@@ -313,7 +313,7 @@
 
   * Initial release
 
-[1.0.0-beta1]: https://github.com/composer/composer/compare/1.0.0-beta1...1.0.0-beta2
+[1.0.0-beta2]: https://github.com/composer/composer/compare/1.0.0-beta1...1.0.0-beta2
 [1.0.0-beta1]: https://github.com/composer/composer/compare/1.0.0-alpha11...1.0.0-beta1
 [1.0.0-alpha11]: https://github.com/composer/composer/compare/1.0.0-alpha10...1.0.0-alpha11
 [1.0.0-alpha10]: https://github.com/composer/composer/compare/1.0.0-alpha9...1.0.0-alpha10