doc: remove support matrix fir Snapshot

As Beta CRD is not supported and also
mentioned kubernetes versions are also
not supported anymore, Removing the
details from the doc for the same reason.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

docs/ceph-csi-upgrade.md

@@ -3,7 +3,6 @@
 - [Ceph-csi Upgrade](#ceph-csi-upgrade)
    - [Pre-upgrade considerations](#pre-upgrade-considerations)
       - [Snapshot-controller and snapshot crd](#snapshot-controller-and-snapshot-crd)
-         - [Snapshot API version support matrix](#snapshot-api-version-support-matrix)
    - [Upgrading from previous releases](#upgrading-from-previous-releases)
    - [Upgrading from v3.8 to v3.9](#upgrading-from-v38-to-v39)
       - [Upgrading CephFS](#upgrading-cephfs)
@@ -61,13 +60,6 @@ Its kubernetes distributor responsibility to install new snapshot
 controller and snapshot CRD. more info can be found
 [here](https://github.com/kubernetes-csi/external-snapshotter/tree/master#usage)
 
-#### Snapshot API version support matrix
-
-| Snapshot API version | Kubernetes Version   | Snapshot-Controller + CRDs Version | Sidecar Version |
-| -------------------- | -------------------- | ---------------------------------- | --------------- |
-| v1beta1              | v1.17 =< k8s < v1.20 | v2.x =< snapshot-controller < v4.x | sidecar >= v2.x |
-| v1                   | k8s >= v1.20         | snapshot-controller >= v4.x        | sidecar >= v2.x |
-
 **Note:** We recommend to use {sidecar, controller, crds} of same version
 
 ## Upgrading from previous releases