build(deps): bump @babel/preset-env from 7.8.3 to 7.8.4 (#11817)

Bumps [@babel/preset-env](https://github.com/babel/babel) from 7.8.3 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/v7.8.3...v7.8.4)

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

package.json

@@ -5,7 +5,7 @@
   "main": "./website/server/index.js",
   "dependencies": {
     "@babel/core": "^7.8.3",
-    "@babel/preset-env": "^7.8.3",
+    "@babel/preset-env": "^7.8.4",
     "@babel/register": "^7.8.3",
     "@google-cloud/trace-agent": "^4.2.5",
     "@slack/client": "^3.8.1",