List 'ROS Infrastructure Team' as the package maintainer (#168)

This package is currently maintained by members of the ROS
infrastructure team at Open Robotics.

Since we're no longer providing an email address for the maintainer
group (and we want folks to use the issue tracker anyway) let's make
sure that the source code and issue tracker are listed in the package
metadata.

Co-authored-by: Steven! Ragnarök <steven@nuclearsandwich.com>

setup.py

@@ -30,9 +30,14 @@
         ]},
     'author': 'Wim Meeussen, Dirk Thomas',
     'author_email': 'wim@hidof.com, dthomas@osrfoundation.org',
-    'maintainer': 'Dirk Thomas',
-    'maintainer_email': 'dthomas@osrfoundation.org',
+    'maintainer': 'ROS Infrastructure Team',
     'url': 'http://wiki.ros.org/rosdistro',
+    'project_urls': {
+        'Source code':
+        'https://github.com/ros-infrastructure/rosdistro',
+        'Issue tracker':
+        'https://github.com/ros-infrastructure/rosdistro/issues',
+    },
     'keywords': ['ROS'],
     'classifiers': [
         'Programming Language :: Python',