Add 'post' step that logs out

[tetchel]

if the workflow is using a self-hosted runner, a user would likely want to log out after their oc workflow finishes.

[Gutodotado24]

Credentials, if desired instead of token.

  # Username and password override token if they are set.
  openshift_username: ${{ env.OPENSHIFT_USER }}
  openshift_password: ${{ secrets.OPENSHIFT_PASSWORD }}