[TASK] Enable 6.1 compatibility

Just adds 2 ViewHelper that were not available
in 6.1 (Switch & Case)

I think if that is all we need to support 6.1
we should do it

Releases: 6.2
Change-Id: I35c80586ff0609f8eaddafdd1ba0edeb38a24697
Reviewed-on: https://review.typo3.org/29764
Reviewed-by: Oliver Klee
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen