add colors property in GradientColor

doric-js/index.d.ts

@@ -956,8 +956,9 @@ declare module 'doric/lib/src/util/color' {
         TL_BR = 7
     }
     export interface GradientColor {
-        start: Color;
-        end: Color;
+        start?: Color;
+        end?: Color;
+        colors?: Array<Color>;
         orientation: GradientOrientation;
     }
 }

doric-js/lib/src/util/color.d.ts

@@ -41,7 +41,8 @@ export declare enum GradientOrientation {
     TL_BR = 7
 }
 export interface GradientColor {
-    start: Color;
-    end: Color;
+    start?: Color;
+    end?: Color;
+    colors?: Array<Color>;
     orientation: GradientOrientation;
 }

doric-js/src/util/color.ts

@@ -91,8 +91,9 @@ export enum GradientOrientation {
 }
 
 export interface GradientColor {
-    start: Color
-    end: Color
+    start?: Color
+    end?: Color
+    colors?: Array<Color>
     orientation: GradientOrientation
 }