Allow installing without specifying the `soroban-cli` as the name

[kalepail]

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% cargo install --git https://github.com/stellar/soroban-cli --features opt 
    Updating git repository `https://github.com/stellar/soroban-cli`
error: multiple packages with binaries found: soroban-cli, soroban-hello. When installing a git repository, cargo will always search the entire repo for any Cargo.toml.
Please specify a package, e.g. `cargo install --git https://github.com/stellar/soroban-cli soroban-cli`.