doc: lift clone feature support to GA

Since kubernetes 1.16 clone ( create a new volume from exisiing volume)
functionality is at Beta state and kubernetes v1.18, the snapshot functionality
has been lifted to GA. Ceph CSI drivers have been supporting this feature
for last few releases and users are heavily using this feature since then.

We also have good amount of e2e test case which cover volume creation
from PVC backend or iow, PVC as a datasource. With that, this PR
proposes of lifting this feature support to GA with v3.4.0 version.

Updates# ceph#2199

Signed-off-by: Humble Chirammal <[email protected]>

README.md

@@ -73,7 +73,7 @@ for its support details.
 |        | Provision Block Mode ROX volume from another volume       | Alpha          | >= v3.0.0          | >= v1.0.0        | Nautilus (>=v14.2.2) | >= v1.16.0         |
 |        | Creating and deleting snapshot                            | GA             | >= v1.0.0          | >= v1.0.0        | Nautilus (>=14.0.0)  | >= v1.17.0         |
 |        | Provision volume from snapshot                            | GA             | >= v1.0.0          | >= v1.0.0        | Nautilus (>=14.0.0)  | >= v1.17.0         |
-|        | Provision volume from another volume                      | Alpha          | >= v1.0.0          | >= v1.0.0        | Nautilus (>=14.0.0)  | >= v1.16.0         |
+|        | Provision volume from another volume                      | GA             | >= v1.0.0          | >= v1.0.0        | Nautilus (>=14.0.0)  | >= v1.16.0         |
 |        | Expand volume                                             | Beta           | >= v2.0.0          | >= v1.1.0        | Nautilus (>=14.0.0)  | >= v1.15.0         |
 |        | Metrics Support                                           | Beta           | >= v1.2.0          | >= v1.1.0        | Nautilus (>=14.0.0)  | >= v1.15.0         |
 |        | Topology Aware Provisioning Support                       | Alpha          | >= v2.1.0          | >= v1.1.0        | Nautilus (>=14.0.0)  | >= v1.14.0         |
@@ -82,7 +82,7 @@ for its support details.
 |        | Dynamically provision, de-provision File mode ROX volume  | Alpha          | >= v3.0.0          | >= v1.0.0        | Nautilus (>=v14.2.2) | >= v1.14.0         |
 |        | Creating and deleting snapshot                            | GA             | >= v3.1.0          | >= v1.0.0        | Octopus (>=v15.2.3)  | >= v1.17.0         |
 |        | Provision volume from snapshot                            | GA             | >= v3.1.0          | >= v1.0.0        | Octopus (>=v15.2.3)  | >= v1.17.0         |
-|        | Provision volume from another volume                      | Alpha          | >= v3.1.0          | >= v1.0.0        | Octopus (>=v15.2.3)  | >= v1.16.0         |
+|        | Provision volume from another volume                      | GA             | >= v3.1.0          | >= v1.0.0        | Octopus (>=v15.2.3)  | >= v1.16.0         |
 |        | Expand volume                                             | Beta           | >= v2.0.0          | >= v1.1.0        | Nautilus (>=v14.2.2) | >= v1.15.0         |
 |        | Metrics                                                   | Beta           | >= v1.2.0          | >= v1.1.0        | Nautilus (>=v14.2.2) | >= v1.15.0         |