fix(frontend/blog/post) fix compatibility with new backend

- switch to axios

app/blog/fetch_posts_list.ts

@@ -1,9 +1,11 @@
+import axios from 'axios';
+
 export default async function fetch_posts_list(): Promise<any> {
-    const response = await fetch(`http://localhost:${ process.env.BACKEND_PORT }/api/get/post_list`);
-    if (!response.ok) {
+    const response = await axios(`http://localhost:${ process.env.BACKEND_PORT }/api/get/post_list`);
+    if (response.status !== 200) {
         throw new Error(response.statusText);
     }
-    return await response.json();
+    return response.data;
 }