Fix AppStream metainfo validation
This fixes the following error and warning detected by appstreamcli validate evolution-rss.metainfo.xml
:
E - evolution-rss.metainfo.xml:evolution-rss:3
The component ID is no reverse domain-name.
W - evolution-rss.metainfo.xml:evolution-rss:32
Found invalid tag: 'updatecontact'. Non-standard tags must be prefixed with
"x-".