Add json-schema to devDependencies

Author: mnovozhylov

package-lock.json

@@ -35,7 +35,8 @@
   },
   "devDependencies": {
     "mocha": "~7.1.2",
-    "ansi-regex": ">=5.0.1"
+    "ansi-regex": ">=5.0.1",
+    "json-schema": ">=0.4.0"
   },
   "engines": {
     "node": "*"