Merge pull request #1865 from okozachenko1203/doc/fix-block-device-volume-name

fix: fix the block device type name in doc

Author: k8s-ci-robot

docs/book/src/topics/crd-changes/v1alpha6-to-v1alpha7.md

@@ -226,7 +226,7 @@ additionalBlockDevices:
 - name: database
   sizeGiB: 50
   storage:
-    type: volume
+    type: Volume
 ```
 
 Here is an example on how to use `additionalBlockDevices` for adding an additional Cinder volume attached
@@ -237,7 +237,7 @@ additionalBlockDevices:
 - name: database
   sizeGiB: 50
   storage:
-    type: volume
+    type: Volume
     volume:
       type: my-volume-type
       availabilityZone: az0