Bump @testing-library/jest-dom from 5.17.0 to 6.0.0 in /backstage

Bumps [@testing-library/jest-dom](https://github.com/testing-library/jest-dom) from 5.17.0 to 6.0.0.
- [Release notes](https://github.com/testing-library/jest-dom/releases)
- [Changelog](https://github.com/testing-library/jest-dom/blob/main/CHANGELOG.md)
- [Commits](testing-library/jest-dom@v5.17.0...v6.0.0)

---
updated-dependencies:
- dependency-name: "@testing-library/jest-dom"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

backstage/packages/app/package.json

@@ -57,7 +57,7 @@
   },
   "devDependencies": {
     "@backstage/test-utils": "^1.2.4",
-    "@testing-library/jest-dom": "^5.10.1",
+    "@testing-library/jest-dom": "^6.0.0",
     "@testing-library/react": "^12.1.3",
     "@testing-library/user-event": "^14.0.0",
     "@types/node": "^20.3.0",

backstage/plugins/viewdocs-react/package.json

@@ -36,7 +36,7 @@
   "devDependencies": {
     "@backstage/cli": "^0.22.1",
     "@backstage/test-utils": "^1.2.6",
-    "@testing-library/jest-dom": "^5.10.1",
+    "@testing-library/jest-dom": "^6.0.0",
     "@testing-library/react": "^12.1.3"
   },
   "files": [

backstage/yarn.lock

@@ -6739,6 +6739,20 @@
     lodash "^4.17.15"
     redent "^3.0.0"
 
+"@testing-library/jest-dom@^6.0.0":
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/@testing-library/jest-dom/-/jest-dom-6.0.0.tgz#d2ba5a3fd13724d5966b3f8cd24d2cedcab4fa76"
+  integrity sha512-Ye2R3+/oM27jir8CzYPmuWdavTaKwNZcu0d22L9pO/vnOYE0wmrtpw79TQJa8H6gV8/i7yd+pLaqeLlA0rTMfg==
+  dependencies:
+    "@adobe/css-tools" "^4.0.1"
+    "@babel/runtime" "^7.9.2"
+    aria-query "^5.0.0"
+    chalk "^3.0.0"
+    css.escape "^1.5.1"
+    dom-accessibility-api "^0.5.6"
+    lodash "^4.17.15"
+    redent "^3.0.0"
+
 "@testing-library/react@^12.1.3":
   version "12.1.5"
   resolved "https://registry.yarnpkg.com/@testing-library/react/-/react-12.1.5.tgz#bb248f72f02a5ac9d949dea07279095fa577963b"