update: adjust documentation for v3 release

- Update CHANGELOG date for v3.0.0 release
- Simplify persistence example in MIGRATION guide
- Update Node.js requirement to 20+ in CONTRIBUTING

Author: tomkp

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
 
-## [3.0.0](https://github.com/tomkp/react-split-pane/compare/v0.1.92...v3.0.0) (2024-12-22)
+## [3.0.0](https://github.com/tomkp/react-split-pane/compare/v0.1.92...v3.0.0) (2025-12-22)
 
 ### ⚠ BREAKING CHANGES
 

CONTRIBUTING.md

@@ -121,7 +121,7 @@ We follow [Conventional Commits](https://www.conventionalcommits.org/):
 
 ### Prerequisites
 
-- Node.js 18+
+- Node.js 20+
 - npm 9+
 
 ### Setup

MIGRATION.md

@@ -300,14 +300,11 @@ import { SplitPane, Pane } from 'react-split-pane';
 import { usePersistence } from 'react-split-pane/persistence';
 
 function App() {
-  const [sizes, setSizes] = usePersistence({
-    key: 'splitPos',
-    defaultSizes: [200],
-  });
+  const [sizes, setSizes] = usePersistence({ key: 'splitPos' });
 
   return (
     <SplitPane onResize={setSizes}>
-      <Pane size={sizes[0]}>Pane 1</Pane>
+      <Pane size={sizes[0] || 200}>Pane 1</Pane>
       <Pane>Pane 2</Pane>
     </SplitPane>
   );