[TASK] Update reference from SVN to Git

Module About TYPO3 shows this text:
The SVN Repository and the ChangeLog can be found here.

This has to be updated to read "Git" instead of "SVN".

Change-Id: I8e708f9e47e5afa5f4528bd308ca13b7f2535364
Resolves: #30171
Releases: 4.5, 4.6
Reviewed-on: http://review.typo3.org/5164
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel