Log Message:
php-composer: Update to 2.0.12

Upstream release notes:
 - Fixed support for new GitHub OAuth token format (#9757)
 - Fixed support for Vagrant/VirtualBox filesystem slowness by adding short
   sleeps in some places (#9627)
 - Fixed unclear error reporting when a package is in the lock file but not in
   the remote repositories (#9750)
 - Fixed processes silently ignoring the CWD when it does not exist
 - Fixed new Windows bin handling to avoid proxying phar files (#9742)
 - Fixed issue extracting archives into paths that already exist, fixing
   problems with some custom installers (composer/installers#479)
 - Fixed support for branch names starting with master/trunk/default (#9739)
 - Fixed self-update to preserve phar file permissions on Windows (#9733)
 - Fixed detection of hg version when localized (#9753)
 - Fixed git execution failures to also include the stdout output (#9720)