Remove mkdirp in favor of fs.mkdirSync builtin

Remove a dependency that is no longer needed with current versions of
Node.

package.json

@@ -80,7 +80,6 @@
     "lodash.debounce": "^4.0.3",
     "lodash.get": "^4.3.0",
     "loose-envify": "^1.4.0",
-    "mkdirp": "^0.5.1",
     "mocha": "^7.0.0",
     "node-uuid": "^1.4.3",
     "npm-packlist": "^2.0.1",

scripts/gulp/create-bundle.js

@@ -12,7 +12,6 @@ const coffeeify = require('coffeeify');
 const exorcist = require('exorcist');
 const log = require('fancy-log');
 const envify = require('loose-envify/custom');
-const mkdirp = require('mkdirp');
 const watchify = require('watchify');
 
 const minifyStream = require('./minify-stream');
@@ -61,7 +60,7 @@ function waitForever() {
  *                   waits forever otherwise.
  */
 module.exports = function createBundle(config, buildOpts) {
-  mkdirp.sync(config.path);
+  fs.mkdirSync(config.path, { recursive: true });
 
   buildOpts = buildOpts || { watch: false };