appdata: Improve appdata for AppStream 1.0

- Add the `<developer><name>` tag
- Mark the `<developer_name>` tag as deprecated
- Improve appstreamcli arguments
- Activate meson tests on Flatpak manifest

build-aux/flatpak/app.drey.Dialect.Devel.json

@@ -33,6 +33,7 @@
         {
             "name" : "dialect",
             "buildsystem" : "meson",
+            "run-tests": true,
             "config-opts": ["-Dprofile=development"],
             "sources" : [
                 {

data/app.drey.Dialect.metainfo.xml.in.in

@@ -29,7 +29,11 @@
   <url type="bugtracker">https://github.com/dialect-app/dialect/issues/</url>
   <url type="translate">https://hosted.weblate.org/engage/dialect/</url>
   <url type="vcs-browser">https://github.com/dialect-app/dialect/</url>
+  <!-- developer_name tag deprecated with Appstream 1.0 -->
   <developer_name>The Dialect Authors</developer_name>
+  <developer id="github.com">
+      <name>The Dialect Authors</name>
+  </developer>
   <content_rating type="oars-1.1" />
 
   <launchable type="desktop-id">@app-id@.desktop</launchable>

data/meson.build

@@ -40,7 +40,7 @@ appstream_file = i18n.merge_file(
 appstreamcli = find_program('appstreamcli', required: false)
 if appstreamcli.found()
   test('Validate appstream file', appstreamcli,
-    args: ['validate', '--no-net', appstream_file.full_path()]
+    args: ['validate', '--no-net', '--explain', appstream_file.full_path()]
   )
 endif