fix: React19 + Typescript fixes (#104)

* chore: avoid using deprecated global `JSX` and properly import type

* fix: react 19 `implicit-ref-callback-return` typescript error

Author: ian-wd

src/index.tsx

@@ -305,7 +305,9 @@ export default class RNSketchCanvas extends React.Component<
           </View>
         </View>
         <SketchCanvas
-          ref={(ref) => (this._sketchCanvas = ref)}
+          ref={(ref) => {
+            this._sketchCanvas = ref;
+          }}
           style={this.props.canvasStyle}
           strokeColor={
             this.state.color +

src/types.tsx

@@ -1,3 +1,4 @@
+import type { JSX } from 'react';
 import type { StyleProp, ViewStyle } from 'react-native';
 
 export type ImageType = 'png' | 'jpg';