message: chore(event-listener): update README with new functionality
  BREAKING CHANGE: event-listener now requires a private key to function properly
diff: @@ -6,6 +6,9 @@ This repository/package is not designed for productive usage. Instead it should
  ## How to use
  +Add a `EVENT_LISTENER_PRIV_KEY` variable that contains the private key to the root `.env` file.
  +Event listener will use this private key to perform transactions on-chain.
  +
  ### Run
  From the root of the monorepo, run the following commands in two separate terminals:
  