build(deps-dev): bump cross-env from 5.2.0 to 7.0.3

Bumps [cross-env](https://github.com/kentcdodds/cross-env) from 5.2.0 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@v5.2.0...v7.0.3)

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

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

package.json

@@ -39,7 +39,7 @@
     "babel-loader": "^8.0.5",
     "babel-plugin-import": "^1.11.0",
     "clean-webpack-plugin": "^0.1.19",
-    "cross-env": "^5.2.0",
+    "cross-env": "^7.0.3",
     "css-loader": "^0.28.11",
     "eslint": "^4.19.1",
     "eslint-config-airbnb": "^17.0.0",