chore(deps-dev): bump cross-env from 6.0.3 to 7.0.3 in /sample-apps

Bumps [cross-env](https://github.com/kentcdodds/cross-env) from 6.0.3 to 7.0.3.
- [Release notes](https://github.com/kentcdodds/cross-env/releases)
- [Changelog](https://github.com/kentcdodds/cross-env/blob/master/CHANGELOG.md)
- [Commits](kentcdodds/cross-env@v6.0.3...v7.0.3)

---
updated-dependencies:
- dependency-name: cross-env
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

sample-apps/package.json

@@ -30,6 +30,6 @@
   },
   "devDependencies": {
     "@lerna/link": "^3.21.0",
-    "cross-env": "^6.0.0"
+    "cross-env": "^7.0.3"
   }
 }