[change] Remove PickerIOS

Ref #1352
Ref facebook/react-native#23313

Author: necolas

packages/babel-plugin-react-native-web/src/moduleMap.js

@@ -33,7 +33,6 @@ module.exports = {
   PanResponder: true,
   PermissionsAndroid: true,
   Picker: true,
-  PickerIOS: true,
   PixelRatio: true,
   Platform: true,
   PointPropType: true,

packages/react-native-web/src/exports/PickerIOS/index.js

@@ -71,7 +71,6 @@ import PointPropType from './exports/PointPropType';
 // compat (components)
 import DrawerLayoutAndroid from './exports/DrawerLayoutAndroid';
 import InputAccessoryView from './exports/InputAccessoryView';
-import PickerIOS from './exports/PickerIOS';
 import ProgressBarAndroid from './exports/ProgressBarAndroid';
 import ProgressViewIOS from './exports/ProgressViewIOS';
 import SegmentedControlIOS from './exports/SegmentedControlIOS';
@@ -166,7 +165,6 @@ export {
   // compat (components)
   DrawerLayoutAndroid,
   InputAccessoryView,
-  PickerIOS,
   ProgressBarAndroid,
   ProgressViewIOS,
   SegmentedControlIOS,