[TASK] gitlab-ci: Rename master to main

Change-Id: I13ca3c60a040c15aca8e259e7c65d33682f37c44
Resolves: #96131
Releases: main
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72349


Tested-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>