dev: Switch default mediawiki image to php 7.3
Bug: T288951
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.
Maintenance on GitLab host gitlab2002.wikimedia.org with reason: Upgrade GitLab to new version starting soon.
Bug: T288951