check proxy skipper before proceeding (#992)

Author: amrnt

middleware/proxy.go

@@ -142,6 +142,10 @@ func ProxyWithConfig(config ProxyConfig) echo.MiddlewareFunc {
 
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
 		return func(c echo.Context) (err error) {
+			if config.Skipper(c) {
+				return next(c)
+			}
+
 			req := c.Request()
 			res := c.Response()
 			tgt := config.Balancer.Next()