device-mgr-doc: Add caution closing tag

To enture that this page is rendered correctly on the Kubernetes
website, the caution tag needs to be closed.

This was missed during the doc write up and review process.

Signed-off-by: Swati Sehgal <[email protected]>

Author: swatisehgal

content/en/docs/concepts/extend-kubernetes/compute-storage-net/device-plugins.md

@@ -176,7 +176,7 @@ guaranteed to be non-breaking.
 Although the Device Manager component of Kubernetes is a generally available feature,
 the _device plugin API_ is not stable. For information on the device plugin API and
 version compatibility, read [Device Plugin API versions](/docs/reference/node/device-plugin-api-versions/).
-{{< caution >}}
+{{< /caution >}}
 
 As a project, Kubernetes recommends that device plugin developers: