Fix mailing list link

Prefer idpy-discuss as the central point to have discussions.

Signed-off-by: Ivan Kanakarakis <ivan.kanak@gmail.com>

Author: c00kiemon5ter

README.md

@@ -81,4 +81,4 @@ OpenID connect provider [SAML2<->OIDC](doc/saml2-to-oidc.md)
 # Contact
 
 If you have any questions regarding operations/deployment of SATOSA please use
-the satosa-users [mailing list](https://lists.sunet.se/listinfo/satosa-users).
+the satosa-users [mailing list](https://lists.sunet.se/postorius/lists/idpy-discuss.lists.sunet.se/).