chore(deps-dev): bump @babel/preset-env from 7.7.1 to 7.8.4

Bumps [@babel/preset-env](https://github.com/babel/babel) from 7.7.1 to 7.8.4.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/compare/v7.7.1...v7.8.4)

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

package.json

@@ -18,7 +18,7 @@
   },
   "devDependencies": {
     "@babel/core": "^7.6.4",
-    "@babel/preset-env": "^7.7.1",
+    "@babel/preset-env": "^7.8.4",
     "@babel/preset-react": "^7.7.0",
     "@types/classnames": "^2.2.9",
     "@types/d3": "^5.7.2",