remove no longer necessary pnpm netlify config

Author: yyx990803

netlify.toml

@@ -1,7 +1,6 @@
 [build.environment]
   NODE_VERSION = "16"
-  NPM_FLAGS = "--version" # prevent Netlify npm install
 
 [build]
   publish = ".vitepress/dist"
-  command = "npx pnpm i --store=node_modules/.pnpm-store && npm run build"
+  command = "pnpm run build"