remove OSIAM (unmaintained since 2018)

- https://osiam.github.io/2018/06/13/active-development-has-stopped.html

README.md

@@ -404,7 +404,6 @@ LDAP servers and other tools to manage accounts and identities.
 - [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`
-- [OSIAM](http://osiam.github.io/) - Secure identity management solution providing REST based services for authentication and authorization.
 - [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`
 - [Samba](https://www.samba.org/) - Active Directory and CIFS protocol implementation. ([Source Code](https://download.samba.org/pub/samba/)) `GPL-3.0` `C`
 - [Smallstep Certificates](https://smallstep.com/certificates/) - A private certificate authority (X.509 & SSH) and related tools for secure automated certificate management. ([Source Code](https://github.com/smallstep/certificates)) `Apache-2.0` `Go`