Steven ledger gen fix

[stevenplatt]

Explain your changes:
This PR is to update the README documentation used for deploying mina testnets using Google Cloud and Terraform infra-as-code. Additionally, this PR fixes a bug that prevented the generate-keys-and-ledger.sh script from properly outputing a testnet ledger.

Explain how you tested your changes:
The change for the ledger gen script has been tested locally by running the generate-key-and-ledger.sh script locally on my machine, using a clean checkout from both develop and compatible to ensue compatibility.

Checklist:

• Modified the current draft of release notes with details on what is completed or incomplete within this project
• Document code purpose, how to use it
  • Mention expected invariants, implicit constraints
• Tests were added for the new behavior
  • Document test purpose, significance of failures
  • Test names should reflect their purpose
• All tests pass (CI will check this if you didn't)
• Serialized types are in stable-versioned modules
• Does this close issues? List them

• Closes Update/Repair generate-keys-and-ledger.sh script for Berkeley incentivized testnet #11139