Bump serve from 6.5.5 to 7.1.3

Bumps [serve](https://github.com/zeit/serve) from 6.5.5 to 7.1.3.
- [Release notes](https://github.com/zeit/serve/releases)
- [Commits](vercel/serve@6.5.5...7.1.3)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -35,7 +35,7 @@
     "rollup": "^0.58.1",
     "rollup-plugin-typescript2": "^0.13.0",
     "rollup-plugin-uglify": "^3.0.0",
-    "serve": "^6.5.5",
+    "serve": "^7.1.3",
     "typescript": "^3.9.7"
   }
 }