docs: unregister service worker

v2/manifest.webmanifest

@@ -0,0 +1,21 @@
+{
+  "name": "Cropper.js",
+  "short_name": "Cropper.js",
+  "description": "JavaScript image cropper.",
+  "start_url": "/cropperjs/v2/index.html",
+  "display": "standalone",
+  "background_color": "#fff",
+  "theme_color": "#39f",
+  "icons": [
+    {
+      "src": "/cropperjs/v2/android-chrome-192x192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    },
+    {
+      "src": "/cropperjs/v2/android-chrome-512.png",
+      "sizes": "512x512",
+      "type": "image/png"
+    }
+  ]
+}

v2/service-worker.js

@@ -0,0 +1,13 @@
+if ('serviceWorker' in navigator) {
+  self.addEventListener('install', () => {
+    self.skipWaiting();
+  });
+  self.addEventListener('activate', (event) => {
+    event.waitUntil(
+      caches.keys()
+      .then((keys) => Promise.all(keys.map((key) => caches.delete(key))))
+      .then(() => navigator.serviceWorker.getRegistrations())
+      .then((registrations) => Promise.all(registrations.map((registration) => registration.unregister())))
+    );
+  });
+}