add apple-touch-icon (#10006)

fixes: https://github.com/go-gitea/gitea/issues/10003

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

templates/base/head.tmpl

@@ -83,7 +83,8 @@
         for the JavaScript code in this page.
 	*/`}}
 	</script>
-	<link rel="shortcut icon" href="{{StaticUrlPrefix}}/img/favicon.png" />
+	<link rel="shortcut icon" href="{{StaticUrlPrefix}}/img/favicon.png">
+	<link rel="apple-touch-icon" href="{{StaticUrlPrefix}}/img/favicon.png">
 	<link rel="mask-icon" href="{{StaticUrlPrefix}}/img/gitea-safari.svg" color="#609926">
 	<link rel="stylesheet" href="{{StaticUrlPrefix}}/vendor/assets/font-awesome/css/font-awesome.min.css">
 	<link rel="stylesheet" href="{{StaticUrlPrefix}}/vendor/assets/octicons/octicons.min.css">