Update SECURITY.md

[miaulalala]

Add Nextcloud HackerOne link instead of mail addresses

[xkill]

Report on nextcloud? Why? (It is roundcube)

[alecpl]

It supposed to be added as an extra channel, not replacing the old one. I still want to be a target for security reports. We can remove Thomas's email, and/or add another one if needed.

[xkill]

But Nextcloud is not Roundcube. I don't know why the security report related to Roundcube have to be reported on Hackersone Nexcloud. Moreover, nextcloud has it's own mail app (it also supports to integrate Roundcube, but is a 3rd party app, not the official one).

It will be great if Roundcube GitHub admins enable the security reports on this repo. But not use a 3rd party app reports to do it.

[alecpl]

https://roundcube.net/news/2023/11/30/nextcloud-the-new-home-for-roundcube

[xkill]

https://roundcube.net/news/2023/11/30/nextcloud-the-new-home-for-roundcube

Thanks for the clarification!!!

[miaulalala]

@alecpl can we merge? Since we discussed this :)