Bump @preact/signals from 1.3.1 to 2.0.0 in /examples/preact

Bumps [@preact/signals](https://github.com/preactjs/signals/tree/HEAD/packages/preact) from 1.3.1 to 2.0.0.
- [Release notes](https://github.com/preactjs/signals/releases)
- [Changelog](https://github.com/preactjs/signals/blob/main/packages/preact/CHANGELOG.md)
- [Commits](https://github.com/preactjs/signals/commits/@preact/[email protected]/packages/preact)

---
updated-dependencies:
- dependency-name: "@preact/signals"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

examples/preact/package.json

@@ -11,7 +11,7 @@
   "author": "Bret Comnes <[email protected]> (https://bret.io/)",
   "license": "MIT",
   "dependencies": {
-    "@preact/signals": "^1.3.0",
+    "@preact/signals": "^2.0.0",
     "highlight.js": "^11.9.0",
     "htm": "^3.1.1",
     "mine.css": "^9.0.1",