Add VolumeGroupSnapshot to ceph-csi README.MD Support Section

[msfrucht]

Describe the feature you'd like to have

Documentation of what version of ceph-csi and for rbd or cephfs or both support for VolumeGroupSnapshot and the minimum version of ceph required.

https://github.com/ceph/ceph-csi?tab=readme-ov-file#support-matrix

What new functionality do you want?

This new feature documented on the README support matrix.

What is the value to the end user? (why is it a priority?)

Confirmation of what version of ceph-csi to install for VolumeGroupSnapshot and ceph version needed to install to use it.

How will we know we have a good solution? (acceptance criteria)

Matches the existing format of support boxes.

Proposed Example:

Plugin	Features	Feature Status	CSI Driver Version	CSI Spec Version	Ceph Cluster Version	Kubernetes Version
RBD	Creating and deleting VolumeGroupSnapshot	Beta	>= v3.13.0	>= v1.11.0	Squid (>=v19.2.0)	>= v1.32.0

Additional context

The latest 3.13 release changelog mentions VolumeGroupSnapshot support for rbd but is not in the support matrix.

[Madhu-1]

@msfrucht we need the next ceph release for the support (as the release is not out we have not updated it in the support matrix). cc @nixpanic

[msfrucht]

@Madhu-1 Thanks for the update. So that would be Ceph 20? Can't find a codename for it at the moment.