docs generation: write package doc as README.md if there are sub-packages

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

docs/reference/universe/kubernetes/README.md

@@ -0,0 +1,31 @@
+---
+sidebar_label: kubernetes
+---
+
+# dagger.io/kubernetes
+
+## #Kubectl
+
+### #Kubectl Inputs
+
+_No input._
+
+### #Kubectl Outputs
+
+_No output._
+
+## #Resources
+
+Apply Kubernetes resources
+
+### #Resources Inputs
+
+| Name             | Type                      | Description                         |
+| -------------    |:-------------:            |:-------------:                      |
+|*namespace*       | `*"default" \| string`    |Kubernetes Namespace to deploy to    |
+|*version*         | `*"v1.19.9" \| string`    |Version of kubectl client            |
+|*kubeconfig*      | `dagger.#Secret`          |Kube config file                     |
+
+### #Resources Outputs
+
+_No output._