update dependencies

index.js

@@ -5,7 +5,7 @@ const Router = require('@koa/router')
 const multer = require('@koa/multer')
 const logger = require('koa-logger')
 const sendfile = require('koa-sendfile')
-const mkdirp = require('mkdirp')
+const mkdirp = require('mkdirp').mkdirp
 const fs = require('fs')
 const { spawn } = require('child_process')
 const { extname, basename, dirname } = require('path')