remove pump.io (unmaintained since april 2022) (#3705)

- 2 commits in 2022, previous was in August 2021
- ref. #3558

README.md

@@ -564,7 +564,6 @@ Simple deployment of [E-mail](https://en.wikipedia.org/wiki/Email) servers, e.g.
 - [phpBB](https://www.phpbb.com/) - Flat-forum bulletin board software solution that can be used to stay in touch with a group of people or can power your entire website. ([Source Code](https://github.com/phpbb/phpbb)) `GPL-2.0` `PHP`
 - [PixelFed](https://pixelfed.social) - Pixelfed is an open-source, federated platform alternate to Instagram. ([Source Code](https://github.com/pixelfed/pixelfed)) `AGPL-3.0` `PHP`
 - [Pleroma](https://pleroma.social) - Federated microblogging server, Mastodon, GNU social, & ActivityPub compatible. ([Source Code](https://git.pleroma.social/pleroma/pleroma)) `AGPL-3.0` `Elixir`
-- [Pump.io](http://pump.io/) - Stream server that does most of what people really want from a social network. ([Source Code](https://github.com/pump-io/pump.io)) `Apache-2.0` `Nodejs`
 - [qpixel](https://codidact.com/) - Q&A-based community knowledge-sharing software. ([Source Code](https://github.com/codidact/qpixel)) `AGPL-3.0` `Ruby`
 - [remark42](https://remark42.com/) - A lightweight and simple comment engine, which doesn't spy on users. It can be embedded into blogs, articles or any other place where readers add comments. ([Demo](https://remark42.com/demo/), [Source Code](https://github.com/umputun/remark42)) `MIT` `Go`
 - [Retrospring](https://github.com/retrospring/retrospring) - A free, open-source social network following the Q/A (question and answer) principle of sites like Formspring, ask.fm or CuriousCat. ([Demo](https://retrospring.net)) `AGPL-3.0` `Ruby/Nodejs`