Adapt values of test files

src/oemof/tabular/examples/datapackages/GHG/data/elements/commodityGHG_import.csv

@@ -1,3 +1,3 @@
 name;type;carrier;amount;bus;emission_bus_0;marginal_cost;output_parameters;emission_factor_co2
-green_gas_import;commodity_ghg;gas;300;gas_bus;co2;2;{"max": [1, 1, 1]};0
+green_gas_import;commodity_ghg;gas;300;gas_bus;co2;20;{"max": [1, 1, 1]};-56
 fossile_gas_import;commodity_ghg;gas;200;gas_bus;co2;10;{"max": [1, 0, 0]};56