message: improve CLI error
diff: @@ -31,6 +31,8 @@ export class Typechain extends TsGeneratorPlugin {
  return new Truffle(ctx);
  case "web3-1.0.0":
  return new Web3(ctx);
  + case undefined:
  + throw new Error(`Please provide --target parameter!`);
  default:
  throw new Error(`Unsupported target ${this.ctx.rawConfig.target}!`);
  }
  