Bump @babel/preset-env from 7.7.7 to 7.8.4

Bumps [@babel/preset-env](https://github.com/babel/babel) from 7.7.7 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/v7.7.7...v7.8.4)

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

package.json

@@ -19,7 +19,7 @@
   "devDependencies": {
     "@babel/cli": "7.7.5",
     "@babel/core": "7.8.4",
-    "@babel/preset-env": "7.7.7",
+    "@babel/preset-env": "7.8.4",
     "@zeit/ncc": "0.21.0",
     "babel-eslint": "10.0.3",
     "eslint": "6.8.0",