chore(docs): add SW to clear cached data in vuepress/pwa (#124)

Author: ota-meshi

docs/.vitepress/public/service-worker.js

@@ -0,0 +1,18 @@
+"use strict"
+
+// https://github.com/NekR/self-destroying-sw
+/* globals self */
+self.addEventListener("install", () => {
+    self.skipWaiting()
+})
+
+self.addEventListener("activate", () => {
+    self.registration
+        .unregister()
+        .then(() => self.clients.matchAll())
+        .then((clients) => {
+            for (const client of clients) {
+                client.navigate(client.url)
+            }
+        })
+})