Update to examples/playbook/sample.capi.yaml

[afoker]

PROBLEM SUMMARY
Looks like the indentation for the sanDns needs to be corrected

STEPS TO REPRODUCE
Use the example formating and sanDns will be ignored.

EXPECTED RESULTS
sanDns NOT to be ignored.

ACTUAL RESULTS
sanDns IS ignored.

ENVIRONMENT DETAILS
latest version of vcert playbook running via SaaS

COMMENTS/WORKAROUNDS
none