Update default values for Windows playbook role

The following discussion from !70 should be addressed:

• @tmaczukin started a discussion: (+2 comments)

  @steveazz Do we really need all of these version entries?

  This is the default playbook file. At the end we're overriding these entries with ansible/group_vars/gcp_role_runner_manager.yml. At the runners: level in this file we're not creating the specific entries for different runners. Just one name: "windows-runner" entry showing how the configuration should look like.

  And I think we should also leave only the default entry in the autoscaler section.

  @ahanselka @cindy Is there a reason for these 1809, 1903 and 1909 entries in this file that I don't see?