Bug: update ajv dependency

**Library version used**
 "0.5.0"

**Language library used with**
JavaScript

**Describe the bug**
This lib depends on   ajv:6.5.2 , which is vulnerable prototype pollution attack. 
https://sca.analysiscenter.veracode.com/vulnerability-database/security/prototype-pollution/javascript/sid-25893


**Expected behaviour/output**
Can we update the dependency to 6.12.3 or later.
