Bump cross-env from 6.0.3 to 7.0.0 (#115)

Bumps [cross-env](https://github.com/kentcdodds/cross-env) from 6.0.3 to 7.0.0.
- [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...v7.0.0)

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

package.json

@@ -37,7 +37,7 @@
     "autoprefixer": "^9.7.4",
     "chalk": "^3.0.0",
     "cheerio": "^1.0.0-rc.3",
-    "cross-env": "^6.0.3",
+    "cross-env": "^7.0.0",
     "eslint": "^6.8.0",
     "find-unused-sass-variables": "^1.0.5",
     "hugo-bin": "^0.51.0",