update docs

website/docs/api.md

@@ -147,6 +147,9 @@ const Component = () => {
 
 ## memo
 
+`memo` is removed in v2. With v2, we can use `React.memo`.
+The description below only applies to v1.
+
 There is a utility function exported from the library.
 
 This should be used instead of `React.memo` if props
@@ -155,7 +158,7 @@ work correctly because a memoized component doesn't always render
 when a parent component renders.
 
 ```javascript
-import { memo } from 'react-tracked';
+import { memo } from 'react-tracked'; // v1 only
 
 const ChildComponent = memo(({ num1, str1, obj1, obj2 }) => {
   // ...

website/docs/caveats.md

@@ -19,7 +19,9 @@ const state2 = useTrackedState();
 You should use `useTrackedState` only once in a component
 if you need referential equality of objects in the state.
 
-## An object referential change doesn't trigger re-render if an property of the object is accessed in previous render
+## An object referential change doesn't trigger re-render if an property of the object is accessed in previous render (v1 only)
+
+:warning: This caveat only applies to v1. Since v2, we don't have such limitations.
 
 ```javascript
 const state = useTrackedState();

website/docs/tutorial-02.md

@@ -192,11 +192,8 @@ export default React.memo(TodoItem);
 ```
 
 This is the TodoItem component.
-We prefer primitive props for memoized components.
-
-If you want to use object props for memoized components,
-you need to use a special [memo](../api#memo) instead of `React.memo`.
-See [example/09](https://github.com/dai-shi/react-tracked/tree/main/examples/09_reactmemo) for the usage.
+We used to prefer primitive props for memoized components with v1.
+With v2, object props are also fine.
 
 ## src/NewTodo.js
 

website/docs/tutorial-03.md

@@ -278,11 +278,8 @@ export default React.memo(TodoItem);
 ```
 
 This is the TodoItem component.
-We prefer primitive props for memoized components.
-
-If you want to use object props for memoized components,
-you need to use a special [memo](../api#memo) instead of `React.memo`.
-See [example/09](https://github.com/dai-shi/react-tracked/tree/main/examples/09_reactmemo) for the usage.
+We used to prefer primitive props for memoized components with v1.
+With v2, object props are also fine.
 
 ## src/components/NewTodo.js