remove reduc.io (unmaintained since January 2022) (#3665)

- WARNING:awesome_lint.py: reduc.io: last updated -386 days, 1:27:30.386559 ago, older than 365 days
- Uses EOL Java 8, no working instructions to build from source, `docker build .` fails
- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/issues/3558

README.md

@@ -2022,7 +2022,6 @@ Before hosting one, please see [shortcomings](https://en.wikipedia.org/wiki/URL_
 - [Kutt](https://kutt.it) - A modern URL shortener with support for custom domains. ([Source Code](https://github.com/thedevs-network/kutt)) `MIT` `Nodejs`
 - [liteshort](https://git.ikl.sh/132ikl/liteshort) - User-friendly, actually lightweight, and configurable URL shortener. `MIT` `Python`
 - [Lstu](https://github.com/ldidry/lstu) - Lightweight URL shortener. `WTFPL` `Perl`
-- [reduc.io](https://github.com/ziyasal/reducio) - URL shortener service written in Scala, using Akka-Http and Redis. `MIT` `Scala`
 - [ReducePy](https://github.com/abdullahselek/ReducePy) - URL shortener service using Tornado and Redis runs on Docker and Kubernetes. `MIT` `Python`
 - [schort](https://github.com/sqozz/schort) - No login, no javascript, just short links. `CC0-1.0` `Python`
 - [Shlink](https://shlink.io) - URL shortener with REST API and command line interface. Includes official progressive web application and docker images. ([Source Code](https://github.com/shlinkio/shlink), [Clients](https://shlink.io/apps)) `MIT` `PHP`