build(deps-dev): bump @open-wc/testing from 3.2.0 to 4.0.0 (#22)

Bumps [@open-wc/testing](https://github.com/open-wc/open-wc/tree/HEAD/packages/testing) from 3.2.0 to 4.0.0.
- [Release notes](https://github.com/open-wc/open-wc/releases)
- [Changelog](https://github.com/open-wc/open-wc/blob/master/packages/testing/CHANGELOG.md)
- [Commits](https://github.com/open-wc/open-wc/commits/@open-wc/[email protected]/packages/testing)

---
updated-dependencies:
- dependency-name: "@open-wc/testing"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -43,7 +43,7 @@
     "devDependencies": {
         "@changesets/changelog-github": "^0.4.8",
         "@changesets/cli": "^2.26.2",
-        "@open-wc/testing": "^3.2.0",
+        "@open-wc/testing": "^4.0.0",
         "@rollup/plugin-commonjs": "^25.0.7",
         "@types/apca-w3": "^0.1.2",
         "@typescript-eslint/eslint-plugin": "^6.10.0",