Add a workaround for Next.js production build bug (#421)

* Add a workaround for Next.js production build bug

Workaround for a Next.js bug when generating a production build
of a Next.js project using Color.js.

See this Github issue for an analysis of the bug:
#260

* Add comment for workaround

src/serialize.js

@@ -27,10 +27,14 @@ export default function serialize (color, {
 	       ?? color.space.getFormat("default")
 	       ?? ColorSpace.DEFAULT_FORMAT;
 
-	inGamut ||= format.toGamut;
+	// The assignment to coords and inGamut needs to stay in the order they are now
+	// The order of the assignment was changed as a workaround for a bug in Next.js
+	// See this issue for details: https://github.com/color-js/color.js/issues/260
 
 	let coords = color.coords.slice(); // clone so we can manipulate it
 
+	inGamut ||= format.toGamut;
+
 	if (inGamut && !checkInGamut(color)) {
 		// FIXME what happens if the color contains NaNs?
 		coords = toGamut(clone(color), inGamut === true ? undefined : inGamut).coords;