synk prototype pollution with ajv versions <6.12.3

[Vijendra Kumar S K]

Security issue with ajv package < 6.12.3 with prototype pollution vulnerability

https://snyk.io/vuln/SNYK-JS-AJV-584908

Upgrade ajv to version 6.12.3 or higher.

[Ahmad Nassri]

new release is out with updated dependencies https://github.com/ahmadnassri/node-har-validator/releases/tag/v5.1.4