Add staking amount to gentx for scripts [stargate][v0.40.0]

[alpe]

With gaiad (d974b27) the ./scripts/two-chainz script fails (on my box) with:
Error: post failed: Post "http://localhost:26657": dial tcp [::1]:26657: connect: connection refused

In the server log:

Error: error during handshake: error on replay: validator set is nil in genesis and still empty after InitChain

The root cause is the new argument for gaiad gentx which was introduced recently.

Usage:
  gaiad gentx [key_name] [amount] [flags]

It affects this script https://github.com/cosmos/relayer/blob/master/scripts/one-chain#L67 and doc

[colin-axner]

looks like it was fixed in #537