Enforce jsx conditional style to disallow && use

[davisshaver]

See convo here: #26 (comment)

It doesn't look like there's an existing eslint rule for this, but there's some code here which we may be able to incorporate as a custom rule: jsx-eslint/eslint-plugin-react#2888

For more on why we want to avoid this pattern, see here: https://kentcdodds.com/blog/use-ternaries-rather-than-and-and-in-jsx

[jamiew]

Oh man I always wondered why ternary was preferred to &&. Nice one for wtfjs

[holic]

Got an old coworker to send me the lint rule/fix + tests! Will see about publishing a plugin that we can pull in here.