Update images with specified width to use figure shortcode (#8475)

Hugo does not support the way the image's max-width was specified before.
This fix will constrain images to always be 50% rather than max out
at 50%, but it is the best we can easily do for now.

Signed-off-by: Misty Stanley-Jones <mistyhacks@google.com>

content/en/docs/concepts/workloads/pods/pod.md

@@ -58,7 +58,7 @@ that means that it exists as long as that pod (with that UID) exists. If that
 pod is deleted for any reason, even if an identical replacement is created, the
 related thing (e.g. volume) is also destroyed and created anew.
 
-![pod diagram](/images/docs/pod.svg){: style="max-width: 50%" }
+{{< figure src="//images/docs/pod.svg" title="pod diagram" width="50%" >}}
 
 *A multi-container pod that contains a file puller and a
 web server that uses a persistent volume for shared storage between the containers.*