fix: add --artifacts-path flag documentation

[LePremierHomme]

Small fix for specifying the --artifacts-path flag needed for seal-genesis command.

Without it, the command fails with the following output:

2024-11-12T08:55:38.110971Z ERROR fendermint/app/src/main.rs:45: failed to execute Options { home_dir: "~/.fendermint", config_dir: None, mode: "dev", global: GlobalArgs { network: Testnet }, command: Genesis(GenesisArgs { genesis_file: "test-network/genesis.json", command: Ipc { command: SealGenesis(SealGenesisArgs { builtin_actors_path: "fendermint/builtin-actors/output/bundle.car", custom_actors_path: "fendermint/actors/output/custom_actors_bundle.car", artifacts_path: None, output_path: "test-network/sealed.car" }) } }) }: ipc enabled but artifacts path not provided

[karlem]

Thanks, it looks good. But I wonder if there are any other places in codebase where it is missing?

[LePremierHomme]

I don't see other examples where this flag is missing, but I do see it pointing to /fendermint/contracts. I'm not sure if this was the old location, or whether it's being populated on-the-fly during a prior automation. If the former, then all these usages should be broken. Any thoughts?