• Add the restart method.

Upgrade to Vue 3.

• Drop an useless dependency (#45).

• Fix an issue of losing time about one second per minute (#43).

• Continue counting down only when the current tab is visible (#37).

• Add missing properties for the progress event (#34).

• Use requestAnimationFrame instead of setTimeout for better performance (#33).

• Add new now option for customizing local time.
• Pause the countdown when the page is hidden and continue the countdown when the page is visible again.