Upgrade: Bump gulp-useref from 3.1.6 to 4.0.0

Bumps [gulp-useref](https://github.com/jonkemp/gulp-useref) from 3.1.6 to 4.0.0.
- [Release notes](https://github.com/jonkemp/gulp-useref/releases)
- [Commits](jonkemp/gulp-useref@v3.1.6...v4.0.0)

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

Author: dependabot-preview[bot]

package.json

@@ -39,7 +39,7 @@
     "gulp-sri": "^0.3.1",
     "gulp-transform": "^3.0.5",
     "gulp-uglify-es": "^1.0.4",
-    "gulp-useref": "^3.1.6",
+    "gulp-useref": "^4.0.0",
     "gulp-zopfli-node": "^1.0.0",
     "hexo": "^3.9.0",
     "hexo-cli": "^3.0.0",