comply with pwa requirements

web/public/manifest.json

@@ -4,7 +4,7 @@
     "icons": [
       {
         "src": "static/img/ntfy_64.png",
-        "sizes": "64x64 32x32 24x24 16x16",
+        "sizes": "64x64",
         "type": "image/png"
       },
       {

web/src/service-worker.js

@@ -21,3 +21,8 @@ clientsClaim();
 // even if you decide not to use precaching. See https://cra.link/PWA
 precacheAndRoute(self.__WB_MANIFEST);
 
+self.addEventListener("fetch", event => {
+    // Dummy event listener to pass PWA installation criteria.
+    console.log('Fetch event fired.')
+})
+