Update README.md

Author: eregon

README.md

@@ -51,8 +51,7 @@ and on Windows by [RubyInstaller2](https://github.com/oneclick/rubyinstaller2).
 The `mingw`, `ucrt` and `mswin` builds are generated by [ruby-loco](https://github.com/MSP-Greg/ruby-loco).
 `ruby-head` is generated by [ruby-dev-builder](https://github.com/ruby/ruby-dev-builder),
 `jruby-head` is generated by [jruby-dev-builder](https://github.com/ruby/jruby-dev-builder),
-`truffleruby-head` is generated by [truffleruby-dev-builder](https://github.com/ruby/truffleruby-dev-builder)
-and `truffleruby+graalvm` is generated by [graalvm-ce-dev-builds](https://github.com/graalvm/graalvm-ce-dev-builds).
+`truffleruby-head` and `truffleruby+graalvm-head` are generated by [truffleruby-dev-builder](https://github.com/ruby/truffleruby-dev-builder).
 The full list of available Ruby versions can be seen in [ruby-builder-versions.json](ruby-builder-versions.json) for Ubuntu and macOS
 (although some combinations are not available, see [the full list](https://github.com/ruby/ruby-builder/releases/tag/toolcache))
 and in [windows-versions.json](windows-versions.json) for Windows.