Bump skynet-js from 2.1.1 to 2.4.0 in /packages/webapp

Bumps [skynet-js](https://github.com/NebulousLabs/skynet-js) from 2.1.1 to 2.4.0.
- [Release notes](https://github.com/NebulousLabs/skynet-js/releases)
- [Changelog](https://github.com/NebulousLabs/skynet-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/NebulousLabs/skynet-js/compare/v2.1.1...v2.4.0)

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

packages/webapp/package.json

@@ -33,7 +33,7 @@
     "react-mailchimp-subscribe": "2.1.0",
     "react-syntax-highlighter": "15.2.1",
     "react-visibility-sensor": "5.1.1",
-    "skynet-js": "2.1.1"
+    "skynet-js": "2.4.0"
   },
   "devDependencies": {
     "cypress": "5.5.0",