[TASK] Update changelog and version to 6.1.0

Change-Id: Ief57c8addc55b6387ffe249169d570fe221b6dd1
Resolves: #47520
Releases: 6.1
Reviewed-on: https://review.typo3.org/20118
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Alexander Schnitzler
Tested-by: Alexander Schnitzler
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters