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

Release-As: 9.1.3

Author: gabcvit

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                  |