bug#49744: cuirass: Invalid RSS feed.

[Mathieu Othacehe]

Hello,

The Cuirass RSS feed is reported as invalid by the W3C checker, see:
https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fci.guix.gnu.org%2Fevents%2Frss%2F%3Fspecification%3Dmaster.

Thanks,

Mathieu