Add developer tag to AppStream metadata

To make the metadata compatible with future AppStream standard version

Author: AsciiWolf

src/io.github.winetricks.Winetricks.metainfo.xml

@@ -6,6 +6,9 @@
   <metadata_license>CC0-1.0</metadata_license>
   <name>Winetricks</name>
   <developer_name>Austin English and others</developer_name>
+  <developer id="io.github.winetricks">
+    <name>Austin English and others</name>
+  </developer>
   <summary>Work around problems and install applications under Wine</summary>
   <description>
     <p>