[TASK] Raise composer installer version number

Version 1.2.1 of the composer installer fixes
an important bug regarding symlinking the autoload.php file.

See: https://github.com/TYPO3/CmsComposerInstallers/commit/f631d729928ce569994ea8e5088491b3eb41f697

Releases: master
Resolves: #67892
Change-Id: I709cc5086d5866b6aae50059a3d74905c8ad79b3
Reviewed-on: http://review.typo3.org/40869


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Alexander Stehlik <alexander.stehlik@gmail.com>
Tested-by: Alexander Stehlik <alexander.stehlik@gmail.com>
Reviewed-by: Stephan Großberndt <stephan@grossberndt.de>
Reviewed-by: Helmut Hummel <helmut.hummel@typo3.org>
Tested-by: Helmut Hummel <helmut.hummel@typo3.org>