Prepare release v304 (heroku#1587)

Co-authored-by: heroku-linguist[bot] <136119646+heroku-linguist[bot]@users.noreply.github.com>

Author: heroku-linguist[bot]

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## [Unreleased]
 
+
+## [v304] - 2025-04-28
+
 - Fix `cp --update=none` on `heroku-20` (https://github.com/heroku/heroku-buildpack-ruby/pull/1586)
 
 ## [v303] - 2025-04-25
@@ -1682,7 +1685,8 @@ Bugfixes:
 * Change gem detection to use lockfile parser
 * use `$RACK_ENV` when thin is detected for rack apps
 
-[unreleased]: https://github.com/heroku/heroku-buildpack-ruby/compare/v303...main
+[unreleased]: https://github.com/heroku/heroku-buildpack-ruby/compare/v304...main
+[v304]: https://github.com/heroku/heroku-buildpack-ruby/compare/v303...v304
 [v303]: https://github.com/heroku/heroku-buildpack-ruby/compare/v302...v303
 [v302]: https://github.com/heroku/heroku-buildpack-ruby/compare/v301...v302
 [v301]: https://github.com/heroku/heroku-buildpack-ruby/compare/v300...v301

lib/language_pack/version.rb

@@ -2,6 +2,6 @@
 
 module LanguagePack
   class LanguagePack::Base
-    BUILDPACK_VERSION = "v303"
+    BUILDPACK_VERSION = "v304"
   end
 end