docs(readme): update README.md (#331)

Release-As: 9.1.3

README.md

@@ -69,7 +69,7 @@ export const Dropdown = () => {
 | `items` | The items for the component to render<br> - Each item should be in the following format:<br>`{label: 'Orange', value: 'orange', key: 'orange', color: 'orange', inputLabel: 'Orange!', testID: 'e2e-orange'}`<br>- `label` and `value` are required<br>- `key`, `color`, `testID`, and `inputLabel` are optional<br>- `key` will be set to equal `label` if not included<br>- `value` can be any data type<br>- If `inputLabel` exists, the TextInput will display that value instead of the `label` | **required**<br>array |
 | `placeholder` | - An override for the default placeholder object with a label of `Select an item...` and a value of `null`<br>- An empty object can be used if you'd like to disable the placeholder entirely | object |
 | `disabled` | Disables interaction with the component | boolean |
-| `value` | Will attempt to locate a matching item from the `items` array by checking each item's `value` property. If found, it will update the component to show that item as selected. If the value is not found, it will default to the first item. | any |
+| `value` | Will attempt to locate a matching item from the `items` array by checking each item's `value` property. If found, it will update the component to show that item as selected. If the value is not found, it will default to the first item. **WARNING:** do not use this attribute on iOS if you plan to allow the user to modify the value from within the `Picker`, use `itemKey` instead.  | any |
 | `itemKey` | Will attempt to locate a matching item from the `items` array by checking each item's `key` property. If found, it will update the component to show that item as selected. If the key is not found, it will attempt to find a matching item by `value` as above. | string, number |
 | `style` | Style overrides for most parts of the component.<br>_More details in [styling](#styling)_ | object |
 | `darkTheme`<br>_iOS only_ | Use the dark theme for the Picker. | boolean |