fix(ajv-keywords): update to version 3.4.1

Closes #72

Author: greenkeeper[bot]

package.json

@@ -50,7 +50,7 @@
     "@semantic-release/git": "4.0.2",
     "@semantic-release/npm": "3.2.4",
     "ajv": "6.5.0",
-    "ajv-keywords": "3.2.0",
+    "ajv-keywords": "3.4.1",
     "codacy-coverage": "3.0.0",
     "commitplease": "3.2.0",
     "coveralls": "3.0.1",