Update zdcPbPb.json

Add paramiter CENTRAL_EVENT_CONFIG with values 2.5 and 1
This parameter is used to fill the histograms relating to the centroid conditioned by the cut on the zems.
This configuration was already present in the zdc.json configuration file used for oxygen and neon. Now, it has also been added for PbPb.

Author: cpuggion84

DATA/production/qc-async/zdcPbPb.json

@@ -57,7 +57,8 @@
           "CENTR_ZNA": "200;-2;2;200;-2;2",
           "CENTR_ZNC": "200;-2;2;200;-2;2",
           "CENTR_ZPA": "2240;0;22.4",
-          "CENTR_ZPC": "2240;-22.4;0"
+          "CENTR_ZPC": "2240;-22.4;0",
+          "CENTRAL_EVENT_CONFIG": "2.5;1"
         }
       }
     }