change the return value of the diff API to an object

[shota-kizawa]

The return value is a boolean, which is difficult to use, so I want to change the return value of the diff API to an object.
For example,

const jsonDiff = require('json-diff')

return jsonDiff.diff({ foo: 'bar' }, { foo: 'baz' });

// Return:
// { foo: { __old: 'bar', __new: 'baz' } }

[shota-kizawa]

add the normalize option to the diff API.