Update devDependencies for React 19, display React version in demo (#383)

I don't suspect any problems but with a major version bump, wanted to
make it clearer to people what React version they were seeing in the
demo, in case of bug reports.

Author: zpao

Diff for: .github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
       fail-fast: false
       matrix:
         react_version:
-          - '18'
+          - '19'
     steps:
       - uses: actions/checkout@v4
       - uses: pnpm/action-setup@v4

Diff for: examples/demo.tsx

@@ -1,5 +1,12 @@
-import React, {useState, StrictMode, useCallback, useEffect} from 'react';
+import React, {
+  useState,
+  StrictMode,
+  useCallback,
+  useEffect,
+  version as reactVersion,
+} from 'react';
 import {createRoot} from 'react-dom/client';
+import {version as reactDOMVersion} from 'react-dom';
 import {version} from '../package.json';
 import {FullDemo} from './full';
 import {DownloadDemo} from './download';
@@ -73,6 +80,12 @@ function Demo() {
           </a>
         </h1>
       </div>
+      <div className="container">
+        <p>
+          Using <code>react@{reactVersion}</code> &{' '}
+          <code>react-dom@{reactDOMVersion}</code>
+        </p>
+      </div>
       <div className="container">
         <label>
           <select

Diff for: package.json

@@ -52,10 +52,10 @@
     "@jest/globals": "^29.5.0",
     "@testing-library/dom": "^10.4.0",
     "@testing-library/jest-dom": "^6.4.8",
-    "@testing-library/react": "^16.0.0",
+    "@testing-library/react": "^16.1.0",
     "@types/node": "^20.4.10",
-    "@types/react": "^18.0.8",
-    "@types/react-dom": "^18.0.3",
+    "@types/react": "^19.0.1",
+    "@types/react-dom": "^19.0.2",
     "@typescript-eslint/eslint-plugin": "^6.3.0",
     "@typescript-eslint/parser": "^6.3.0",
     "eslint": "^8.6.0",
@@ -68,8 +68,8 @@
     "jest": "^29.2.2",
     "jest-environment-jsdom": "^29.7.0",
     "prettier": "^3.0.1",
-    "react": "^18.0.0",
-    "react-dom": "^18.0.0",
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0",
     "ts-jest": "^29.1.0",
     "tsup": "^8.0.2",
     "typescript": "^5.0.4"