Update DEBUG variable in cli.ts

Update the DEBUG variable to use LOZ_DEBUG environment variable for
consistency and clarity.

Generated by gpt-3.5-turbo

src/cli.ts

@@ -2,7 +2,7 @@
 import * as yargs from "yargs";
 import { Loz } from "./index";
 
-const LOZ_DEBUG = process.env.DEBUG === "true" ? true : false;
+const DEBUG = process.env.LOZ_DEBUG === "true" ? true : false;
 
 const args = yargs
   .wrap(null)