[gimp-macos-build] doap: add Lukas Oberhuber as co-maintainer.

[Jehan <jehanp src gnome org>]

commit bb06e74c2d5faa68af1808d34864bba65ed2c3ce
Author: Jehan <jehan girinstud io>
Date:   Sun Apr 24 12:10:26 2022 +0200

    doap: add Lukas Oberhuber as co-maintainer.
    
    However you look at it, Lukas has been co-maintainer for the macOS
    package for some time now. I'm surprised he was not added in the doap
    file already. Fixed! :-)

 gimp-macos-build.doap | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/gimp-macos-build.doap b/gimp-macos-build.doap
index 1812e41..0c4d49b 100644
--- a/gimp-macos-build.doap
+++ b/gimp-macos-build.doap
@@ -28,4 +28,11 @@
     </foaf:Person>
   </maintainer>
 
+  <maintainer>
+    <foaf:Person>
+      <foaf:name>Lukas Oberhuber</foaf:name>
+      <gnome:userid>lukaso</gnome:userid>
+    </foaf:Person>
+  </maintainer>
+
 </Project>