Upgrade del requirement from ^4.0.0 to ^4.1.0 (#12)

Updates the requirements on [del](https://github.com/sindresorhus/del) to permit the latest version.

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -26,7 +26,7 @@
     "url": "https://github.com/huiyifyj/Proxy-pac.js/issues"
   },
   "devDependencies": {
-    "del": "^4.0.0",
+    "del": "^4.1.0",
     "gulp": "^4.0.0",
     "gulp-concat": "^2.6.1",
     "gulp-header": "^2.0.7",