Deprecate validator-ajv6 in favor of validator-ajv8 before end of Beta

[heath-freenome]

Prerequisites

• [X] I have searched the existing issues
• [X] I understand that providing a SSCCE example is tremendously useful to the maintainers.
• [X] I have read the documentation
• [ ] Ideally, I'm providing a sample JSFiddle or a shared playground link demonstrating the issue.

What theme are you using?

core

Version

5.0.0-beta.6

Current Behavior

Now that we have the validator-ajv8 we are going to want to deprecate the validator-ajv6. Update ALL of the documentation and tests so that validator-ajv8 is used.