Bump cross-env from 5.2.1 to 6.0.3

Bumps [cross-env](https://github.com/kentcdodds/cross-env) from 5.2.1 to 6.0.3.
- [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...v6.0.3)

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

Author: dependabot-preview[bot]

package-lock.json

@@ -29,7 +29,7 @@
     "@types/node": "^12.7.5",
     "@typescript-eslint/eslint-plugin": "^2.3.3",
     "@typescript-eslint/parser": "^2.3.3",
-    "cross-env": "^5.2.0",
+    "cross-env": "^6.0.3",
     "discord.js": "^11.5.1",
     "dotenv": "^8.1.0",
     "eslint": "^5.16.0",