appdata: Improve appdata for AppStream 1.0

- Add the `<developer><name>` tag
- Mark the `<developer_name>` tag as deprecated
- Use appstreamcli to validate appdata
- Fix a broken release description

data/meson.build

@@ -79,3 +79,13 @@ i18n.merge_file(
   install: true,
   install_dir: ev_appstreamdir,
 )
+
+# Validate Appdata
+appstreamcli = find_program('appstreamcli', required: false)
+if (appstreamcli.found())
+  test('validate-appdata',
+    appstreamcli,
+    args: ['validate', '--no-net', '--explain', metainfo],
+    workdir: meson.current_build_dir()
+  )
+endif

data/org.gnome.Evince.metainfo.xml.in

@@ -45,6 +45,11 @@
   <url type="donation">https://www.gnome.org/donate/</url>
   <url type="vcs-browser">https://gitlab.gnome.org/GNOME/evince/</url>
   <project_group>GNOME</project_group>
+  <!-- developer_name tag deprecated with Appstream 1.0 -->
+  <developer_name>The GNOME Project</developer_name>
+  <developer id="gnome.org">
+    <name>The GNOME Project</name>
+  </developer>
   <update_contact>https://discourse.gnome.org/tag/evince</update_contact>
   <kudos>
     <kudo>AppMenu</kudo>
@@ -219,7 +224,9 @@
       </issues>
     </release>
     <release version="40.1" date="2021-03-26">
-      <description>Restore libraries soname.</description>
+      <description>
+        <p>Restore libraries soname.</p>
+      </description>
     </release>
     <release version="40.0" date="2021-03-26">
       <issues>