remove IndieAuth (unmaintained since 2021) (#579)

- ref. https://github.com/awesome-foss/awesome-sysadmin/issues/405

README.md

@@ -388,7 +388,6 @@ Miscellaneous utilities and web interfaces for identity management systems.
 - [BounCA](https://bounca.org/) - A personal SSL Key / Certificate Authority web-based tool for creating self-signed certificates. ([Source Code](https://gitlab.com/bounca/bounca/)) `Apache-2.0` `Python`
 - [easy-rsa](https://github.com/OpenVPN/easy-rsa) - Bash script to build and manage a PKI CA. `GPL-2.0` `Shell`
 - [Fusion Directory](https://www.fusiondirectory.org) - Improve the Management of the services and the company directory based on OpenLDAP. ([Source Code](https://github.com/fusiondirectory/fusiondirectory)) `GPL-2.0` `PHP`
-- [Indieauth](https://indieauth.com/) - Sign in with your domain name (using the rel-me-auth protocol). ([Source Code](https://github.com/aaronpk/IndieAuth.com)) `Apache-2.0` `Ruby`
 - [LDAP Account Manager (LAM)](https://www.ldap-account-manager.org/lamcms/) - Web frontend for managing entries (e.g. users, groups, DHCP settings) stored in an LDAP directory. ([Source Code](https://github.com/LDAPAccountManager/lam/)) `GPL-3.0` `PHP`
 - [Libravatar](https://www.libravatar.org/) - Libravatar is a service which delivers your avatar (profile picture) to other websites. ([Source Code](https://git.linux-kernel.at/oliver/ivatar/)) `AGPL-3.0` `Python`
 - [Pomerium](https://www.pomerium.io/) - An identity and context aware access-proxy inspired by BeyondCorp. ([Source Code](https://github.com/pomerium/pomerium)) `Apache-2.0` `Docker/Go`