Add Sparkle to auto-update

[yllan]

No description provided.

[yllan]

Seems like Sparkle 1 doesn't support sandboxed app.

Need to

1. Switch to Sparkle 2.0 beta
2. Turn off sandbox
3. Downloading from a website instead of auto-update https://sparkle-project.org/documentation/publishing/#publishing-an-update

[yllan]

Due to incorrect setting for 0.1.3, we can't get the next version auto-updated either way. 👎
Should use integer for CFBundleVersion.

The only way I can come up with is to use release notes to hint the user to download. Luckily we are in the early stage so there's no one using this app.