fix(deps): update dependency next to v15.5.6 (#7601)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -13,7 +13,7 @@
   "dependencies": {
     "@theguild/components": "9.11.1",
     "@theguild/remark-mermaid": "0.3.0",
-    "next": "15.5.5",
+    "next": "15.5.6",
     "next-sitemap": "4.2.3",
     "react": "19.2.0",
     "react-dom": "19.2.0"