README: complete code block

Author: dustymabe

README.md

@@ -70,7 +70,7 @@ First, we need to convert the image to an OCI archive:
 skopeo copy containers-storage:quay.io/myorg/myrepo:mytag oci-archive:my-custom-rhcos.ociarchive
 # from a registry
 skopeo copy --authfile /path/to/pull-secret docker://registry.com/org/repo:latest oci-archive:./my-custom-rhcos.ociarchive
-``
+```
 
 You can now take that ociarchive and create a disk image for a
 platform (i.e. `qemu`, `metal` or `gcp`). First you need an