Create page that lists supported doc versions. (#6882)

_data/docs-home.yml

@@ -2,6 +2,7 @@ bigheader: "Documentation Home"
 abstract: "Documentation for using and learning about Kubernetes."
 toc:
 - docs/home/index.md
+- docs/home/supported-doc-versions.md
 
 - title: Release Notes
   path: https://git.k8s.io/kubernetes/CHANGELOG.md

docs/home/supported-doc-versions.md

@@ -0,0 +1,29 @@
+---
+title: Supported Versions of the Kubernetes Documentation
+---
+
+{% capture overview %}
+
+This website contains documentation for the current version of Kubernetes
+and the four previous versions of Kubernetes.
+
+{% endcapture %}
+
+{% capture body %}
+
+## Current version
+
+The current version is
+[{{page.version}}](/).
+
+## Previous versions
+
+{% for v in page.versions %}
+{% if v.version != page.version %}
+* [{{ v.version }}]({{v.url}})
+{% endif %}
+{% endfor %}
+
+{% endcapture %}
+
+{% include templates/concept.md %}