Update runtime version, fix appdata

com.example.play_sounds.json

 {
     "app-id": "com.example.play_sounds",
     "runtime": "org.gnome.Platform",
-    "runtime-version": "3.32",
+    "runtime-version": "3.34",
     "sdk": "org.gnome.Sdk",
     "command": "play-sounds",
     "finish-args": [

data/com.example.play_sounds.appdata.xml.in

@@ -4,6 +4,6 @@
     <metadata_license>CC0-1.0</metadata_license>
     <project_license>GPL-3.0-or-later</project_license>
     <description>
-        Play a selection of sounds.
+	<p>Play a selection of sounds.</p>
     </description>
 </component>