There are the steps for developers on the Dart Dev Compiler team to publish a new version to pub. The edit steps can be done directly on github if preferred.
If you have not uploaded before, you may need to ask an existing uploader to grant you permission. They'll need to run:
> pub uploader add <your-email-address>
Update the following files with the new version number:
Update CHANGELOG.md with notable changes since the last release.
Make sure the above is committed to github master. Make sure you have those updates in your local master:
> git pull
> git tag <new-version-number> # E.g., git tag 0.1.14
> git push --tags
Check the github site to make sure the tag appears there under the Branch button.
> pub lish
Check pub.dartlang.org to ensure the latest DDC is there.