chore: clean up README

[skip ci]

Author: unknwon

README.md

@@ -1,17 +1,15 @@
 # captcha
 
 [![GitHub Workflow Status](https://img.shields.io/github/workflow/status/flamego/captcha/Go?logo=github&style=for-the-badge)](https://github.com/flamego/captcha/actions?query=workflow%3AGo)
-[![Codecov](https://img.shields.io/codecov/c/gh/flamego/captcha?logo=codecov&style=for-the-badge)](https://app.codecov.io/gh/flamego/captcha)
 [![GoDoc](https://img.shields.io/badge/GoDoc-Reference-blue?style=for-the-badge&logo=go)](https://pkg.go.dev/github.com/flamego/captcha?tab=doc)
-[![Sourcegraph](https://img.shields.io/badge/view%20on-Sourcegraph-brightgreen.svg?style=for-the-badge&logo=sourcegraph)](https://sourcegraph.com/github.com/flamego/captcha)
 
 Package captcha is a middleware that provides captcha service for [Flamego](https://github.com/flamego/flamego).
 
 ## Installation
 
-The minimum requirement of Go is **1.24**.
-
-	go get github.com/flamego/captcha
+```zsh
+go get github.com/flamego/captcha
+```
 
 ## Getting started