fix: bump verkle genesis generator (#486)

go-verkle depns changes, we need this bump to be compatible for the
current verkle tests

src/participant_network.star

@@ -125,7 +125,7 @@ def launch_participant_network(
         elif network_params.electra_fork_epoch != None:
             if network_params.electra_fork_epoch == 0:
                 ethereum_genesis_generator_image = (
-                    "ethpandaops/ethereum-genesis-generator:4.0.0-rc.5"
+                    "ethpandaops/ethereum-genesis-generator:4.0.0-rc.6"
                 )
             else:
                 ethereum_genesis_generator_image = (