Add developer name to MetaInfo

This is required by Flathub

Author: Matoking

data/com.github.Matoking.protontricks.metainfo.xml

@@ -29,6 +29,9 @@
        such as launching external Windows executables. This is often useful when a game requires closed-source runtime libraries or applications
        that are not included with Proton.</p>
   </description>
+  <developer id="matoking.com">
+    <name>Janne Pulkkinen</name>
+  </developer>
   <url type="homepage">https://github.com/Matoking/protontricks</url>
   <url type="help">https://github.com/Matoking/protontricks#readme</url>
   <url type="bugtracker">https://github.com/Matoking/protontricks/issues</url>