refactor(kitchen): prefer kitchen.yml to .kitchen.yml

* Quoting from https://kitchen.ci/docs/getting-started/kitchen-yml/:
  - As of test-kitchen 1.21.0, we now prefer `kitchen.yml` over `.kitchen.yml`.
  - This preference applies to `kitchen.local.yml` as well.
  - This is backward compatible so the dot versions continue to work.

.gitignore

@@ -105,6 +105,7 @@ tests/integration/cloud/providers/pki/minions
 
 # Kitchen tests files
 .kitchen.local.yml
+kitchen.local.yml
 .kitchen/
 .bundle/
 Gemfile.lock