Add `upgrade-support` link on issue creation (#28411)

Summary:
This PR adds a https://github.com/react-native-community/upgrade-support link for the user when creating an issue.
Changelog:
[Internal]

Pull Request resolved: https://github.com/facebook/react-native/pull/28411

Reviewed By: cpojer

Differential Revision: D20714274

Pulled By: hramos

fbshipit-source-id: 4ca42224a50e386b95f21f0fb236a917e1b6b982