Update dependency next to v15

package.json

@@ -18,9 +18,9 @@
   "dependencies": {
     "clsx": "1.2.1",
     "concurrently": "8.0.1",
-    "next": "13.4.2",
-    "react": "19.1.0",
-    "react-dom": "19.1.0",
+    "next": "15.1.8",
+    "react": "18.2.0",
+    "react-dom": "18.2.0",
     "react-markdown": "8.0.7",
     "remark-gfm": "3.0.1",
     "server-only": "0.0.1",
@@ -30,10 +30,10 @@
   },
   "devDependencies": {
     "@types/node": "18.16.9",
-    "@types/react": "19.1.8",
-    "@types/react-dom": "19.1.6",
+    "@types/react": "18.2.6",
+    "@types/react-dom": "18.2.4",
     "autoprefixer": "10.4.14",
-    "eslint": "9.32.0",
+    "eslint": "8.40.0",
     "eslint-config-next": "latest",
     "postcss": "8.4.23",
     "prettier": "2.8.8",