Add repo link to about page

Author: chrisglein

src/About.tsx

@@ -4,6 +4,7 @@ import {
   Text,
   View,
 } from 'react-native';
+import {Hyperlink} from './Controls';
 import {Popup} from 'react-native-windows';
 import {StylesContext} from './Styles';
 
@@ -26,6 +27,7 @@ function AboutPopup({show, close}: AboutPopupProps): JSX.Element {
           </View>
           <Text style={{fontWeight: 'bold'}}>About</Text>
         </View>
+        <Hyperlink url='https://github.com/chrisglein/artificial-chat/'/>
         <View style={{marginTop: 12, alignSelf: 'flex-end'}}>
           <Button
             title="OK"