add announcement page

src/core/bg/index.js

@@ -80,3 +80,11 @@ browser.runtime.onMessage.addListener((message, sender) => {
 if (browser.runtime.onMessageExternal) {
 	browser.runtime.onMessageExternal.addListener(externalMesssages.onMessage);
 }
+
+browser.runtime.onInstalled.addListener((details) => {
+	if (details.reason == "update" && details.previousVersion.startsWith("1.21")) {
+		browser.tabs.create({
+			url: "https://gildas-lormeau.github.io/singlefile-updates/version-1-22.html"
+		});
+	}
+});

src/lib/single-file/browser-polyfill/chrome-browser-polyfill.js

@@ -334,6 +334,9 @@ if (typeof globalThis == "undefined") {
 						}
 					})
 				},
+				onInstalled: {
+					addListener: listener => nativeAPI.runtime.onInstalled.addListener(listener)
+				},
 				sendMessage: message => new Promise((resolve, reject) => {
 					nativeAPI.runtime.sendMessage(message, response => {
 						if (nativeAPI.runtime.lastError) {