fix(deps): update dependency hexo-generator-index to v4

Author: renovate[bot]

package-lock.json

@@ -18,7 +18,7 @@
     "hexo-asset-link": "^2.2.3",
     "hexo-generator-archive": "^2.0.0",
     "hexo-generator-category": "^2.0.0",
-    "hexo-generator-index": "^3.0.0",
+    "hexo-generator-index": "^4.0.0",
     "hexo-generator-search": "^2.4.3",
     "hexo-generator-tag": "^2.0.0",
     "hexo-renderer-ejs": "^2.0.0",