doc: updated Go.dev badge

Author: esimov

README.md

@@ -1,6 +1,6 @@
 # stackblur-go
 
-[![GoDoc](https://godoc.org/github.com/golang/gddo?status.svg)](https://godoc.org/github.com/esimov/stackblur-go)
+[![Go Reference](https://pkg.go.dev/badge/github.com/esimov/stackblur-go.svg)](https://pkg.go.dev/github.com/esimov/stackblur-go)
 [![build](https://github.com/esimov/stackblur-go/actions/workflows/build.yml/badge.svg)](https://github.com/esimov/stackblur-go/actions/workflows/build.yml)
 
 Go port of Mario Klingemann's [Stackblur](http://incubator.quasimondo.com/processing/fast_blur_deluxe.php) algorithm.