hack: add docs generation/validation

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

hack/update-docs

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+. $(dirname $0)/util
+set -eu
+
+output=$(mktemp -d -t buildx-output.XXXXXXXXXX)
+
+buildxCmd build \
+  --target "update" \
+  --output "type=local,dest=$output" \
+  --file "./hack/dockerfiles/docs.Dockerfile" \
+  .
+
+rm -rf ./docs/reference/*
+cp -R "$output"/out/* ./docs/
+rm -rf $output