Fix the environment variable

This was using k8S_AUTH_CONTEXT with a lowercase k.  That doesn't match
with any of the other K8s stuff so users would probably be confused why
their envvar wasn't working.

plugins/connection/oc.py

@@ -85,7 +85,7 @@ DOCUMENTATION = '''
         vars:
           - name: ansible_oc_context
         env:
-          - name: k8S_AUTH_CONTEXT
+          - name: K8S_AUTH_CONTEXT
       oc_host:
         description:
           - URL for accessing the API.