Bump cross-env from 5.2.1 to 7.0.3

Bumps [cross-env](https://github.com/kentcdodds/cross-env) from 5.2.1 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@v5.2.1...v7.0.3)

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

Author: dependabot-preview[bot]

package.json

@@ -58,7 +58,7 @@
     "@types/node": "^8.0.19",
     "@types/node-json-db": "0.0.1",
     "@types/sequelize": "^4.0.68",
-    "cross-env": "^5.1.3",
+    "cross-env": "^7.0.3",
     "del": "^6.0.0",
     "eslint": "^6.5.1",
     "gulp": "^4.0.2",