Edit burger menu to close when one of the links is clicked

[Emir Demirbag]

Current behaviour: burger menu icon needs to be clicked to trigger the menu from open to closed; nav bar links currently fail to toggle the menu when clicked.

Desired behaviour: clicking one of the nav bar links (including the site logo) toggles the menu closed; only burger menu links – not nav bar links in general – should trigger this behaviour; toggling should apply only when the link clicked is different to the current page, e.g. if the current page is "about", clicking the "contact" link will trigger the event, while the "about" link will do nothing.

See this example (site: https://gatsby-netlify-cms.netlify.com/).