refactor(adjustHue): remove redundant %

Since the % operation is already performed inside `hslToRgb()` in `src/internalHelpers/_hslToRgb.js`
(which `adjustHue()` eventually calls through `toColorString()`), this % is completely redundant.

refactor styled-components#437

src/color/adjustHue.js

@@ -32,7 +32,7 @@ function adjustHue(degree: number | string, color: string): string {
   const hslColor = parseToHsl(color)
   return toColorString({
     ...hslColor,
-    hue: (hslColor.hue + parseFloat(degree)) % 360,
+    hue: hslColor.hue + parseFloat(degree),
   })
 }