Added GalSim 2.0+ compatibility for the field _input_objs when using proxy catalogs.

Author: sweverett

balrog/balrog_injection.py

@@ -475,7 +475,11 @@ def generate_stars(self, config, realization):
 
                     # Make proxy catalog
                     galsim.config.ProcessInput(gs_config)
-                    cat_proxy = gs_config['input_objs'][input_type][0]
+                    try:
+                        cat_proxy = gs_config['input_objs'][input_type][0]
+                    except KeyError:
+                        # The field name changed in GalSim 2.0+
+                        cat_proxy = gs_config['_input_objs'][input_type][0]
 
                     # pudb.set_trace()
                     # If all stars in Sahar's catalogs were guaranteed to be in the