fix: Add tintColor type definition.

Author: mamoru0217

src/index.d.ts

@@ -109,6 +109,13 @@ export interface FastImageProperties {
      * Style
      */
     style?: StyleProp<ImageStyle>
+ 
+    /**
+     * TintColor
+     * 
+     * If supplied, changes the color of all the non-transparent pixels to the given color.
+     */        
+    tintColor?: number | string
 
     /**
      * A unique identifier for this element to be used in UI Automation testing scripts.