Use blubber v0.21.1 to build blubber
Updated the README.md as well to mention the newest version.
Bug: T356908
How to register an account on GitLab. To prevent spam, new accounts are locked until approved by an admin or the approver bot. You can also file an unlock request to expedite access.
Support: mw:GitLab, how to host a project on GitLab, #wikimedia-gitlab on libera.chat, #GitLab on Phabricator.
Updated the README.md as well to mention the newest version.
Bug: T356908