adjust config to upstream changes

Author: lindnemi

config/config.de.yaml

@@ -417,6 +417,7 @@ solving:
   runtime: 12h
   mem_mb: 70000 #30000 is OK for 22 nodes, 365H; 140000 for 22 nodes 3H; 400000 for 44 nodes 3H
   options:
+    custom_extra_functionality: "../scripts/pypsa-de/additional_functionality.py"
     assign_all_duals: true
     load_shedding: false
     skip_iterations: true # settings for post-discretization: false