feat: minimum OS 10.14 (for notifications)

QLOPML/PreviewViewController.m

@@ -15,7 +15,9 @@
 - (void)preparePreviewOfFileAtURL:(NSURL *)url completionHandler:(void (^)(NSError * _Nullable))handler {
 	NSData *data = generateHTMLData(url, [NSBundle mainBundle], NO);
 	// sure, we could use `WKWebView`, but that requires the `com.apple.security.network.client` entitlement
+#pragma clang diagnostic ignored "-Wdeprecated"
 	WebView *web = [[WebView alloc] initWithFrame:self.view.bounds];
+#pragma clang diagnostic pop
 	web.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;
 	[self.view addSubview:web];
 //	[web.mainFrame loadHTMLString:html baseURL:nil];