Adding BlockStorage v3 version support

Change-Id: Ia0c304731f2f1f35d80a9168cd9bb2ca3a8a08b9
diff --git a/openstack/blockstorage/v3/volumes/doc.go b/openstack/blockstorage/v3/volumes/doc.go
new file mode 100644
index 0000000..307b8b1
--- /dev/null
+++ b/openstack/blockstorage/v3/volumes/doc.go
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+// Package volumes provides information and interaction with volumes in the
+// OpenStack Block Storage service. A volume is a detachable block storage
+// device, akin to a USB hard drive. It can only be attached to one instance at
+// a time.
+package volumes