remove Helpy (unmaintained since 2021) (#3737)

- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/issues/3558
- https://demo.helpy.io/en : HTTPSConnectionPool(host='demo.helpy.io', port=443): Read timed out. (read timeout=10)
- WARNING:awesome_lint.py: Helpy: last updated -543 days, 11:21:53.478882 ago, older than 365 days

README.md

@@ -1996,7 +1996,6 @@ _Related: [Task Management & To-do Lists](#task-management--to-do-lists), [Softw
 - [Erxes](https://erxes.io/install/) - Marketing, sales, and customer service platform designed to help businesses attract more engaged customers. ([Demo](https://demo.erxes.io/), [Source Code](https://github.com/erxes/erxes)) `GPL-3.0` `Javascript`
 - [FreeScout](https://github.com/freescout-helpdesk/freescout) - Open source clone of Help Scout: email-based customer support application, help desk and shared mailbox. `AGPL-3.0` `PHP`
 - [GlitchTip](https://glitchtip.com) - Open source error-tracking app. GlitchTip collects errors reported by your app. ([Source Code](https://gitlab.com/glitchtip/glitchtip)) `MIT` `Python`
-- [Helpy](https://github.com/helpyio/helpy) - Helpy is a modern, open source helpdesk customer support application. Features include knowledgebase, community discussions and support tickets integrated with email. ([Demo](https://demo.helpy.io/en)) `MIT` `Ruby`
 - [Iguana](https://github.com/iguana-project/iguana) - Iguana is an open source issue management system with a kanban board. `CC-BY-SA-4.0` `Python/Docker`
 - [ITFlow](https://itflow.org) - Client IT Documentation, Ticketing, Invoicing and Accounting Web Application for MSPs (Managed Service Providers). ([Demo](https://demo.itflow.org), [Source Code](https://github.com/itflow-org/itflow)) `GPL-3.0` `PHP`
 - [MantisBT](https://www.mantisbt.org/) - Self hosted bug tracker, fits best for software development. ([Demo](https://www.mantisbt.org/bugs/my_view_page.php), [Source Code](https://github.com/mantisbt/mantisbt)) `GPL-2.0` `PHP`