doc: add badges.

Author: ldez

readme.md

@@ -1,5 +1,8 @@
 # gomoddirectives
 
+[![Sponsor](https://img.shields.io/badge/Sponsor%20me-%E2%9D%A4%EF%B8%8F-pink)](https://github.com/sponsors/ldez)
+[![Build Status](https://github.com/ldez/gomoddirectives/workflows/Main/badge.svg?branch=master)](https://github.com/ldez/gomoddirectives/actions)
+
 A linter that handle [`replace`](https://golang.org/ref/mod#go-mod-file-replace), [`retract`](https://golang.org/ref/mod#go-mod-file-retract), [`exclude`](https://golang.org/ref/mod#go-mod-file-exclude) directives into `go.mod`.
 
 Features: