Problem/Motivation
ComposerProjectTemplatesTest is currently fails in HEAD when using the 7.4.x/7.3.x php containers.
This is due to the fact that the containers are built every day, and on Oct 28th, Composer 2 was released, thus upgrading those containers specifically.
If we build any new containers, HEAD will break.
Steps to reproduce
Run a core test using 7.4.x-dev or 7.3.x-dev php containers:
See https://www.drupal.org/pift-ci-job/1879647
Proposed resolution
The version of composer installed on the container should not be the one core tests rely on. We should change any invocations of 'composer' to ./vendor/bin/composer to ensure that we are using the version of composer that our dev dependencies specify for our tests.
We should open *another* followup to determine why our test fails in composer 2, or fix it as part of
https://www.drupal.org/project/drupal/issues/3128631
Remaining tasks
Write a patch