Set additional information on command's 'app'

For completeness

command.go

@@ -157,6 +157,12 @@ func (c Command) startApp(ctx *Context) error {
 	app.Commands = c.Subcommands
 	app.Flags = c.Flags
 	app.HideHelp = c.HideHelp
+
+	app.Version = ctx.App.Version
+	app.HideVersion = ctx.App.HideVersion
+	app.Compiled = ctx.App.Compiled
+	app.Author = ctx.App.Author
+	app.Email = ctx.App.Email
 	app.Writer = ctx.App.Writer
 
 	// bash completion