Bump cross-env from 5.2.1 to 6.0.0

Bumps [cross-env](https://github.com/kentcdodds/cross-env) from 5.2.1 to 6.0.0.
- [Release notes](https://github.com/kentcdodds/cross-env/releases)
- [Changelog](https://github.com/kentcdodds/cross-env/blob/master/CHANGELOG.md)
- [Commits](https://github.com/kentcdodds/cross-env/compare/v5.2.1...v6.0.0)

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

package.json

@@ -11,7 +11,7 @@
     "apply-loader": "2.0.0",
     "awesome-typescript-loader": "^5.0.0",
     "core-js": "^3.2.0",
-    "cross-env": "5.2.1",
+    "cross-env": "6.0.0",
     "css-loader": "3.2.0",
     "electron": "^6.0.9",
     "electron-builder": "^21.2.0",