periodic-containerdisks-push-nightly failing due to an error occurred during publishing of the docs

[lyarwood]

/kind bug

What happened:

https://testgrid.k8s.io/kubevirt-containerdisks-periodics#periodic-containerdisks-push-nightly

https://prow.ci.kubevirt.io/view/gs/kubevirt-prow/logs/periodic-containerdisks-push-nightly/1641621405709635584

time="2023-03-31T02:16:43Z" level=error msg="error marshaling example for \"rhcos\": error rendering template for \"rhcos\": template: description:1:13: executing \"description\" at <ToTitle>: wrong type for value; expected language.Tag; got string" name=rhcos version=4.12
time="2023-03-31T02:16:43Z" level=error msg="error marshaling example for \"centos\": error rendering template for \"centos\": template: description:1:13: executing \"description\" at <ToTitle>: wrong type for value; expected language.Tag; got string" name=centos version=7-2009
time="2023-03-31T02:16:43Z" level=error msg="error marshaling example for \"centos-stream\": error rendering template for \"centos-stream\": template: description:1:13: executing \"description\" at <ToTitle>: wrong type for value; expected language.Tag; got string" name=centos-stream version=9
time="2023-03-31T02:16:43Z" level=error msg="error marshaling example for \"ubuntu\": error rendering template for \"ubuntu\": template: description:1:13: executing \"description\" at <ToTitle>: wrong type for value; expected language.Tag; got string" name=ubuntu version=22.04
Error: an error occurred during publishing of the docs
Usage:
  medius docs publish [flags]
Flags:
  -h, --help                     help for publish
      --quay-token-file string   quay.io oauth token file
      --registry string          target registry for the containerdisks (default "quay.io/containerdisks")
Global Flags:
      --dry-run             don't publish anything (default true)
      --focus string        Focus on a specific containerdisk
      --insecure-skip-tls   allow connecting to insecure registries
time="2023-03-31T02:16:43Z" level=fatal msg="an error occurred during publishing of the docs"

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• KubeVirt version (use virtctl version):
• Kubernetes version (use kubectl version):
• common-templates version:
• VM or VMI specifications:
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others: