Document the new version field for installer config.

utils/docs/config.md

@@ -7,6 +7,7 @@ The default location this config file will be written to ~/.config/openshift/ins
 ## Example
 
 ```
+version: v1
 variant: openshift-enterprise
 variant_version: 3.0
 ansible_ssh_user: root
@@ -32,6 +33,10 @@ hosts:
 
 ## Primary Settings
 
+### version
+
+Indicates the version of configuration this file was written with. Current implementation is v1.
+
 ### variant
 
 The OpenShift variant to install. Currently valid options are: