message: Update node version in docs
  Since we use methods like .flat() a ^11.0.0 version is required. Docker image currently uses 12, so the version in the docs is being updated to match.
diff: @@ -5,7 +5,7 @@ The dashboard is the main UI component of the Kubeapps project. Written in Javas
  ## Prerequisites
  - [Git](https://git-scm.com/)
  -- [Node 8.x](https://nodejs.org/)
  +- [Node 12.x](https://nodejs.org/)
  - [Yarn](https://yarnpkg.com)
  - [Kubernetes cluster (v1.8+)](https://kubernetes.io/docs/setup/)
  - [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/)
  