renamed combined obs example config

baselines/combined_tree_local_conflict_obs/sparse_small_apex_maxdepth2_spmaxdepth30.yaml

-flatland-sparse-small-density-cnn-apex:
+flatland-sparse-small-combined-obs-tree-local-conflict-apex:
     run: APEX
     env: flatland_sparse
     stop:
@@ -48,12 +48,15 @@ flatland-sparse-small-density-cnn-apex:
         evaluation_config:
             explore: False
             env_config:
-                observation: density
+                observation: combined
                 observation_config:
-                    width: 25
-                    height: 25
-                    max_t: 1000
-                    encoding: exp_decay
+                    tree:
+                      max_depth: 2
+                      shortest_path_max_depth: 30
+                    localConflict:
+                      max_depth: 2
+                      shortest_path_max_depth: 30
+                      n_local: 5
                 regenerate_rail_on_reset: True
                 regenerate_schedule_on_reset: True
                 render: False