Use Adwaita's about window and remove devel style

data/window.blp

@@ -9,7 +9,6 @@ template RugbyAppWindow : ApplicationWindow {
   title: "Rugby";
   default-height: 600;
   default-width: 400;
-  styles ["devel"]
 
   [titlebar]
   HeaderBar {

src/main.c

@@ -30,12 +30,13 @@ about_activated (G_GNUC_UNUSED GSimpleAction *simple,
 
     const char *authors[] = { "Bruce Cowan", NULL };
 
-    gtk_show_about_dialog (window,
-                           "logo-icon-name", "face-wink",
-                           "program-name", "Rugby",
+
+    adw_show_about_window (window,
+                           "application-icon", "face-wink",
+                           "application-name", "Rugby",
                            "copyright", "Copyright 2012–2022 Bruce Cowan",
                            "license-type", GTK_LICENSE_GPL_3_0,
-                           "authors", authors,
+                           "developers", authors,
                            "comments", "Rugby scores possibilities program",
                            "version", VERSION,
                            NULL);