Update Canonical Example in README to use correct import (#3)

README.md

@@ -33,7 +33,7 @@ import (
 	"fmt"
 	"time"
 
-	"github.com/gin-gonic/contrib/gzip"
+	"github.com/gin-contrib/gzip"
 	"gopkg.in/gin-gonic/gin.v1"
 )