fix(ios): Xcode12 build run on device crash

ios/ARTNode.m

@@ -8,6 +8,7 @@
 #import "ARTNode.h"
 
 #import "ARTContainer.h"
+#import "RCTConvert+ART.h"
 
 @implementation ARTNode
 
@@ -79,7 +80,9 @@ - (void)renderContentTo:(CGContextRef)context {
   CGContextSaveGState(context);
   CGContextConcatCTM(context, self.transform);
   CGContextSetAlpha(context, self.opacity);
-  CGContextSetShadowWithColor(context, self.shadow.offset, self.shadow.blur, self.shadow.color.CGColor);
+  UIColor *color = [UIColor colorWithCGColor:[RCTConvert CGColor:@(self.shadow.color)]];
+  color = [color colorWithAlphaComponent:self.shadow.alpha];
+  CGContextSetShadowWithColor(context, self.shadow.offset, self.shadow.blur, color.CGColor);
 }
 
 - (void)renderLayerTo:(CGContextRef)context

ios/ARTShadow.h

@@ -8,5 +8,6 @@
 typedef struct {
   CGSize offset;
   CGFloat blur;
-  UIColor* color;
+  CGFloat alpha;
+  CGFloat color;
 } ARTShadow;

ios/RCTConvert+ART.m

@@ -164,12 +164,9 @@ + (ARTBrush *)ARTBrush:(id)json
 + (ARTShadow)ARTShadow:(id)json
 {
   NSArray *arr = [self NSArray:json];
-
-  UIColor *color = [UIColor colorWithCGColor:[self CGColor:[arr objectAtIndex:0]]];
-  color = [color colorWithAlphaComponent:[[arr objectAtIndex:1] floatValue]];
-
   return (ARTShadow){
-    .color = color,
+    .color = [[arr objectAtIndex:0] doubleValue],
+    .alpha = [[arr objectAtIndex:1] floatValue],
     .blur = [[arr objectAtIndex:2] floatValue],
     .offset = (CGSize){
       .width = [[arr objectAtIndex:3] floatValue],