added announcement bar

lib/client/getLatestVersion.ts

@@ -0,0 +1,16 @@
+export default async function getLatestVersion(setShowAnnouncement: Function) {
+  const announcementId = localStorage.getItem("announcementId");
+
+  const response = await fetch(
+    `https://blog.linkwarden.app/latest-announcement.json`
+  );
+
+  const data = await response.json();
+
+  const latestAnnouncement = data.id;
+
+  if (announcementId !== latestAnnouncement) {
+    setShowAnnouncement(true);
+    localStorage.setItem("announcementId", latestAnnouncement);
+  }
+}