add build command

package.json

@@ -5,6 +5,9 @@
   "workspaces": [
     "packages/*"
   ],
+  "scripts": {
+    "build": "yarn workspace @hono/hello build"
+  },
   "license": "MIT",
   "private": true,
   "repository": {
@@ -32,4 +35,4 @@
     "ts-jest": "^28.0.5",
     "typescript": "^4.7.4"
   }
-}
+}