* Update metadata.json

* updating change log for release

In some cases a custom Etcd installation or running Etcd as a deployment
in the Kubernetes cluster itself is desired.

This commit adds a feature flag for enabling/disable the installation of
an external Etcd via this module.

removing unused etcd template

* fixes instructions to use env file, with correct filename

* spelling mistake

updating rakefile for ci

This commit is needed to support Puppet 6, where we fixed this bug:
https://tickets.puppetlabs.com/browse/PUP-9112

We need to test for both an undef vaule (backwards compatible) and nil
(in Puppet 6 and beyond)

* fixes yaml chars when hash is empty

* testing k8s 1.12

* adding in bind port

* adding in working 1.12 template

* working 1.12 config

* documenting new param and adding existing features to new template for parity

* fixing variables in prep for in module data at a later stage

* renaming templates and using correct version variable

* fix linting

* adds in k8s version variable

* adding in version for alpha1 template

* adds in option to specify alternate image repo

* fixes update of etcd version

* Support customized kubelet configuration.

Support is added for both the alpha1 and alpha3 config.yaml formats.
Before the alpha3 format, kubelet configuration could be added via
kubeadm_extra_config.  However, that doesn't work with the alpha3
format since kubelet configuration is passed via a separate YAML
document with kind == KubeletConfiguration:
https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha3#hdr-Kubeadm_init_configuration_types

* Document kubelet_extra_config in README