Add function to fetch the newest version of the app & also a popup.

components/checkAppVersion.ts

@@ -0,0 +1,10 @@
+import currentVersion from "~/versionTag";
+export default async function newestVersion() {
+  const current = currentVersion();
+  const req = await fetch("/api/version");
+  const res = await req.json();
+  if (current !== res.version) {
+    return false;
+  }
+  return true;
+}