A fix of install instructions (#5483)

* Update from https://github.com/kubernetes-sigs/kubespray/issues/4318#issuecomment-470161397

* Woops I missed a spot

README.md

@@ -28,7 +28,7 @@ cp -rfp inventory/sample inventory/mycluster
 
 # Update Ansible inventory file with inventory builder
 declare -a IPS=(10.10.1.3 10.10.1.4 10.10.1.5)
-CONFIG_FILE=inventory/mycluster/inventory.ini python3 contrib/inventory_builder/inventory.py ${IPS[@]}
+CONFIG_FILE=inventory/mycluster/hosts.yaml python3 contrib/inventory_builder/inventory.py ${IPS[@]}
 
 # Review and change parameters under ``inventory/mycluster/group_vars``
 cat inventory/mycluster/group_vars/all/all.yml
@@ -38,7 +38,7 @@ cat inventory/mycluster/group_vars/k8s-cluster/k8s-cluster.yml
 # The option `--become` is required, as for example writing SSL keys in /etc/,
 # installing packages and interacting with various systemd daemons.
 # Without --become the playbook will fail to run!
-ansible-playbook -i inventory/mycluster/inventory.ini --become --become-user=root cluster.yml
+ansible-playbook -i inventory/mycluster/hosts.yaml  --become --become-user=root cluster.yml
 ```
 
 Note: When Ansible is already installed via system packages on the control machine, other python packages installed via `sudo pip install -r requirements.txt` will go to a different directory tree (e.g. `/usr/local/lib/python2.7/dist-packages` on Ubuntu) from Ansible's (e.g. `/usr/lib/python2.7/dist-packages/ansible` still on Ubuntu).