Setting an `ariaSelected` prop works in the latest Safari because elements have
an `ariaSelected` property as part of the Accessibility Object Model
implementation [1]. This is not yet implemented in Chrome however, so
the `ariaSelected` prop gets mapped to an `ariaselected` attribute. We
need to set the `aria-selected` attribute however.

[1] https://github.com/WICG/aom/blob/gh-pages/explainer.md#reflecting-aria-attributes