Wikibase Travis CI is currently broken on master because we call composer self-update in our install script and that updates Composer to the newly released v2, which the Wikimedia composer-merge-plugin isn't compatible with. (see T248908)
Acceptance criteria
- Travis CI for Wikibase CI is no longer broken on master
Notes
Task to fix this properly: T266455: Make Wikibase Secondary CI use Composer 2 (currently stalled due to the incompatible plugin mentioned above)