feat(package.json, readme.md): add engines object to package.json

Add ability for readme.md to identify npm usage

none

Author: Jennifer Luker

package.json

@@ -66,5 +66,8 @@
     "typescript": "2.3.3",
     "validate-commit-msg": "2.14.0",
     "wallaby-webpack": "*"
+  },
+  "engines": {
+    "npm": ">=2.0.0"
   }
 }