Bump @zeit/ncc from 0.20.5 to 0.21.0

Bumps [@zeit/ncc](https://github.com/zeit/ncc) from 0.20.5 to 0.21.0.
- [Release notes](https://github.com/zeit/ncc/releases)
- [Commits](https://github.com/zeit/ncc/compare/0.20.5...0.21.0)

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

package.json

@@ -20,7 +20,7 @@
     "@babel/cli": "7.8.4",
     "@babel/core": "7.8.4",
     "@babel/preset-env": "7.8.4",
-    "@zeit/ncc": "0.20.5",
+    "@zeit/ncc": "0.21.0",
     "babel-eslint": "10.0.3",
     "eslint": "6.8.0",
     "eslint-config-airbnb": "18.0.1",