Add blubber.yaml, gitlab-ci.yml
Adds blubber.yaml and gitlab-ci.yml to run tests in ci
Bug: #T290260
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.
Adds blubber.yaml and gitlab-ci.yml to run tests in ci
Bug: #T290260