Remove Pi-Hole (moved to awesome-selfhosted/DNS) (#505)

- https://github.com/awesome-selfhosted/awesome-selfhosted#dns
- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/pull/3942

README.md

@@ -367,7 +367,6 @@ _Related: [DNS - Servers](#dns---servers)_
 - [DomainMOD](https://domainmod.org) - Manage your domains and other internet assets in a central location. ([Source Code](https://github.com/domainmod/domainmod.git)) `GPL-3.0` `PHP`
 - [nsupdate.info](https://www.nsupdate.info/) - Dynamic DNS service. ([Demo](https://www.nsupdate.info/account/register/), [Source Code](https://github.com/nsupdate-info/nsupdate.info)) `BSD-3-Clause` `Python`
 - [octoDNS](https://github.com/github/octodns) - DNS as code - Tools for managing DNS across multiple providers. `MIT` `Python`
-- [Pi-hole](https://pi-hole.net/) - A blackhole for Internet qdvertisements with a GUI for management and monitoring. ([Source Code](https://github.com/pi-hole/pi-hole)) `EUPL-1.2` `Shell/PHP`
 - [Poweradmin](https://www.poweradmin.org/) - Web-based DNS control panel for PowerDNS server. ([Source Code](https://github.com/poweradmin/poweradmin)) `GPL-3.0` `PHP`
 - [SPF Toolbox](https://spftoolbox.com) - Application to look up DNS records such as SPF, MX, Whois, and more. ([Source Code](https://github.com/charlesabarnes/SPFtoolbox)) `MIT` `PHP`