chore: use http.Status* instead of hard code (#1482)

examples/favicon/main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"net/http"
+
 	"github.com/gin-gonic/gin"
 	"github.com/thinkerou/favicon"
 )
@@ -9,7 +11,7 @@ func main() {
 	app := gin.Default()
 	app.Use(favicon.New("./favicon.ico"))
 	app.GET("/ping", func(c *gin.Context) {
-		c.String(200, "Hello favicon.")
+		c.String(http.StatusOK, "Hello favicon.")
 	})
 	app.Run(":8080")
 }