rss: set content-type to xml
rss: set content-type to xml

 * Work on https://github.com/sebsauvage/MinigalNano/issues/48
jniggemann/MinigalNano,inscriptionweb/MinigalNano,inscriptionweb/MinigalNano,sebsauvage/MinigalNano,sebsauvage/MinigalNano,jniggemann/MinigalNano,jniggemann/MinigalNano,inscriptionweb/MinigalNano,sebsauvage/MinigalNano