Merge branch 'develop' of https://github.com/cloudevents/sdk-javascript into develop

Author: fabiojose

lib/specs/spec_0_2.js

@@ -16,8 +16,9 @@ const reserved = {
 
 const schema = require("../../ext/spec_0_2.json");
 
-// Default options
-const ajv = new Ajv();
+const ajv = new Ajv({
+  extendRefs: true //  validate all keywords in the schemas with $ref (the default behaviour in versions before 5.0.0)
+});
 
 const validate = ajv.compile(schema);