examples: replace all app.Run(iris.Addr(...)) with app.Listen just for the shake of simplicity, both are doing the same exact thing as it's described on the http listening first example.

Former-commit-id: d20afb2e899aee658a8e0ed1693357798df93462

_examples/routing/writing-a-middleware/globally/main.go

@@ -29,7 +29,7 @@ func main() {
 	app.UseGlobal(before)
 	app.DoneGlobal(after)
 
-	app.Run(iris.Addr(":8080"))
+	app.Listen(":8080")
 }
 
 func before(ctx iris.Context) {