Merge pull request #24779 from kbhawkey/fix-feature-state-volume

fix CSIMigration feature state

Author: k8s-ci-robot

content/en/docs/concepts/storage/volumes.md

@@ -1367,7 +1367,7 @@ For more information on how to develop a CSI driver, refer to the
 
 #### Migrating to CSI drivers from in-tree plugins
 
-{{< feature-state for_k8s_version="v1.17" state="alpha" >}}
+{{< feature-state for_k8s_version="v1.17" state="beta" >}}
 
 The `CSIMigration` feature, when enabled, directs operations against existing in-tree
 plugins to corresponding CSI plugins (which are expected to be installed and configured).