Update appdata file to comply with Flathub requirements

[RayJW]

The current appdata file has no tag, which is required by the Flathub guidelines. For the time being, I worked around this in my PR by applying a patch, although it would obviously be nicer if this can be fixed upstream :)

Also, is there a reason for the odd naming? I couldn't find any explanation why the file was renamed to xml.in.in for the file type.

[staticssleever668]

Hi! .in suffix usually means file is preprocessed. In our case twice for whatever reason.

piper/data/meson.build

Lines 38 to 47 in 0f72869

	appdata = configure_file(input: 'org.freedesktop.Piper.appdata.xml.in.in',
	output: 'org.freedesktop.Piper.appdata.xml.in',
	configuration: conf)
	appdata = i18n.merge_file(input: appdata,
	output: 'org.freedesktop.Piper.appdata.xml',
	type: 'xml',
	po_dir: podir,
	install: true,
	install_dir: metainfodir)

it would obviously be nicer if this can be fixed upstream

PRs are welcome. :)

[RayJW]

Hi! .in suffix usually means file is preprocessed. In our case twice for whatever reason.

While I was aware of the input suffix, this is honestly the first time I've encountered it stacked. Interesting :)

it would obviously be nicer if this can be fixed upstream

PRs are welcome. :)

#993 ;)