docs: fix broken links (#6)

* fix: fix broken links

* docs: add badge

README.md

@@ -3,7 +3,7 @@
 [![crates](https://img.shields.io/crates/v/yaml-adapter)](https://crates.io/crates/yaml-adapter)
 [![docs](https://docs.rs/yaml-adapter/badge.svg)](https://docs.rs/yaml-adapter)
 ![download](https://img.shields.io/crates/d/yaml-adapter)
-![ci](https://github.com/casbin-rs/yaml-adapter/workflows/ci/badge.svg)
+[![ci](https://github.com/casbin-rs/yaml-adapter/actions/workflows/ci.yml/badge.svg)](https://github.com/casbin-rs/yaml-adapter/actions/workflows/ci.yml)
 
 Yaml Adapter is a [yaml](https://github.com/dtolnay/serde-yaml) adapter for [Casbin-rs](https://github.com/casbin/casbin-rs). With this library, Casbin can load policy from yaml fromat file or save policy into it with fully asynchronous support.