chore: update readme badge [ci skip]

README.md

@@ -1,7 +1,7 @@
 # Vuex
 
 [![npm](https://img.shields.io/npm/v/vuex.svg)](https://npmjs.com/package/vuex)
-[![ci status](https://circleci.com/gh/vuejs/vuex/tree/main.png?style=shield)](https://circleci.com/gh/vuejs/vuex)
+[![ci status](https://github.com/vuejs/vuex/actions/workflows/ci.yml/badge.svg)](https://github.com/vuejs/vuex/actions/workflows/ci.yml)
 
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