build: restore dnt task

Author: vicary

deno.json

@@ -4,6 +4,7 @@
   "version": "0.0.0-development",
   "license": "MIT",
   "tasks": {
+    "build": "deno run -A dnt.ts",
     "check": "deno check src/index.ts",
     "dev": "deno run --allow-all src/index.ts",
     "lint": "deno lint",