35: Updated Accordion and AccordionItem logic

[Caleb-Ellis]

Done

• Updated Accordion and AccordionItem logic to allow single-item-open behaviour
• Fixed bug where Accordion was hard-coded with children
• Fixed Accordion styling

QA

• Pull code
• Run yarn clean, yarn build and yarn serve
• Run yarn lint and yarn test and ensure there are no linting or testing errors
• Verify the Accordion component has single-item-only behaviour on Storybook

Fixes

Fixes #35, fixes #43

[webteam-app]

No ./run found. Unable to start demo.

[barrymcgee]

@Caleb-Ellis Two small points in code, otherwise, looks good.

[barrymcgee]

@Caleb-Ellis Also to note, for QA you no longer need to yarn build before yarn serve as the preserve script handles it.

Adding pre or post to any script name in a package.json will run it either before or after.

[Caleb-Ellis]

@barrymcgee good catches. I was never 100% certain why props had to be passed to the constructor. Good to know... you don't