chore: use node native module instead of mkdirp package

lib/index.js

@@ -1,6 +1,5 @@
 const async = require('async')
 const fs = require('fs')
-const mkdirp = require('mkdirp')
 const path = require('path')
 const gifsicle = require('./image/gifsicle')
 const gmagick = require('./image/gmagick')
@@ -18,7 +17,7 @@ const DEFAULT_STILL_SEEK_SECONDS = 1
 */
 exports.image = function (source, target, options, callback) {
   // create target folder if needed
-  mkdirp.sync(path.dirname(target))
+  fs.mkdirSync(path.dirname(target), { recursive: true })
 
   // when processing a GIF
   // - if asking for an animated target, process with Gifsicle
@@ -49,7 +48,7 @@ exports.image = function (source, target, options, callback) {
 
 exports.video = function (source, target, options, callback) {
   // create target folder if needed
-  mkdirp.sync(path.dirname(target))
+  fs.mkdirSync(path.dirname(target), { recursive: true })
 
   // run ffmpeg to create the downsized video
   const args = ffargs.prepare(source, target, options)
@@ -61,7 +60,8 @@ exports.video = function (source, target, options, callback) {
 */
 exports.still = function (source, target, options, callback) {
   // create target folder if needed
-  mkdirp.sync(path.dirname(target))
+  fs.mkdirSync(path.dirname(target), { recursive: true })
+
   async.series([
     (next) => extractFrame(source, target, options, next),
     (next) => exports.image(target, target, options, next)

package.json

@@ -15,7 +15,6 @@
     "async": "^3.2.4",
     "debug": "^4.3.4",
     "gm": "^1.25.0",
-    "mkdirp": "^2.1.5",
     "split": "^1.0.1",
     "tmp": "^0.2.1"
   },