Update json requirement

[jkugler]

All tests pass, but using simplecov doesn't give me a lot of confidence in the level of code coverage, especially the code that might be parsing and usin JSON.

Update json required version.

Description

Bump json requirement to < 3.0.0

Motivation and Context

The requirement to use json < 2 conflicts with rest-client which can use versions later. Depending on which gets require'd first, ruby will throw an error saying it can't resolve the dependency.

How Has This Been Tested?

I ran rake.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have updated the Changelog following the conventions laid out on Keep A Changelog

Known Caveats

[cwjohnston]

I built a pre-release gem with this change and it's working as expected in my lab. 👍