Merge pull request #675 from thebuilder/fix/deprecated-react-dom-act

fix: support old act from react-dom

Author: thebuilder

src/test-utils.ts

@@ -1,7 +1,13 @@
-import { act } from "react";
+import * as React from "react";
+import * as DeprecatedReactTestUtils from "react-dom/test-utils";
+
 declare global {
   var IS_REACT_ACT_ENVIRONMENT: boolean;
 }
+
+const act =
+  typeof React.act === "function" ? React.act : DeprecatedReactTestUtils.act;
+
 type Item = {
   callback: IntersectionObserverCallback;
   elements: Set<Element>;