chore: change build command to npm run build

Author: Yukaii

package.json

@@ -37,7 +37,7 @@
     "benchmark-deps": "npm install --prefix benchmark/extra/ -g [email protected] [email protected] markdown-it/markdown-it.git#2.2.1",
     "specsplit": "support/specsplit.mjs good -o test/fixtures/commonmark/good.txt && support/specsplit.mjs bad -o test/fixtures/commonmark/bad.txt && support/specsplit.mjs",
     "todo": "grep 'TODO' -n -r ./lib 2>/dev/null",
-    "prepublishOnly": "build"
+    "prepublishOnly": "npm run build"
   },
   "files": [
     "index.mjs",