chore(yamllint): update ignored paths and add octal-values [skip ci]

* Automated using myii/ssf-formula#59

.yamllint

@@ -7,9 +7,11 @@ extends: default
 # Files to ignore completely
 # 1. All YAML files under directory `node_modules/`, introduced during the Travis run
 # 2. Any SLS files under directory `test/`, which are actually state files
+# 3. Any YAML files under directory `.kitchen/`, introduced during local testing
 ignore: |
   node_modules/
   test/**/states/**/*.sls
+  .kitchen/
 
 yaml-files:
   # Default settings
@@ -28,3 +30,6 @@ rules:
     # Increase from default of `80`
     # Based on https://github.com/PyCQA/flake8-bugbear#opinionated-warnings (`B950`)
     max: 88
+  octal-values:
+    forbid-implicit-octal: true
+    forbid-explicit-octal: true