update kitchen.io url, lint fix README markdown
update kitchen.io url, lint fix README markdown

The email address is also out of date.

It would be nice to get this listed on https://kitchen.ci/docs/drivers/, but perhaps that only makes sense after a Fog driver for Linode APIv4 exists and this project (or a new APIv4 version) adapts to that fog driver.
ssplatt/kitchen-linode