Add turb as maven_artifact maintainer (#37424)

and flag chrisisbeef as ignored, because he has been inactive for many months already.

.github/BOTMETA.yml

@@ -517,7 +517,9 @@ files:
   $modules/packaging/language/cpanm.py:
   $modules/packaging/language/easy_install.py: mattupstate
   $modules/packaging/language/gem.py: $team_ansible
-  $modules/packaging/language/maven_artifact.py: chrisisbeef tumbl3w33d
+  $modules/packaging/language/maven_artifact.py:
+    ignored: chrisisbeef
+    maintainers: tumbl3w33d turb
   $modules/packaging/language/npm.py:
     ignored: chrishoffman
     maintainers: shane-walker xcambar