Version 6.0.0

• Fixed issue with API of UICircularRingStyle which made it impossible to have both a gradient and outer ring style, etc.
• Refactor way that UICircularRingValueFormatter works. It's now a simple protocol which anyone can conform to. There are two concrete implementations from 5.0.0 which can still be used, however, they're now structs so cannot be mutated.

Breaking Changes

• Due to the fact that both the .style property now doesnt allow setting .gradient, this API has been broken. Instead, use the new .gradientOptions property to set a gradient, and .style if you need extra styling on top of gradient
• Because the value formatter are now structs, they cannot be modified with . syntax. Instead create a brand new formatter and assign to the .valueFormatter property. This will be over all much better in the future, less state and structs are cool!