Updates the /docs redirect to always go to what is globally defined as the latest version

Signed-off-by: Pete Lumbis <pete@upbound.io>

content/docs/_index.md

@@ -2,5 +2,5 @@
 title: crossplane
 weight: 401
 layout: redirect
-to: https://crossplane.io/docs/v1.9/
+docs_root: true
 ---

themes/crossplane/layouts/_default/redirect.html

@@ -1 +1,5 @@
+{{ if .Params.docs_root }}
+{{ partial "redirect" (dict "dest" (printf "https://crossplane.io/docs/v%s/" (string .Site.Params.latest) ) ) }}
+{{ else }}
 {{ partial "redirect" (dict "dest" .Params.to) }}
+{{ end }}