chore: correct the hex doc url

Author: zhongwencool

README.md

@@ -7,7 +7,7 @@
 [![MIT License](https://img.shields.io/hexpm/l/observer_cli.svg)](https://hex.pm/packages/observer_cli)
 [![Hex.pm Version](https://img.shields.io/hexpm/v/observer_cli.svg)](https://hex.pm/packages/observer_cli)
 [![Hex.pm Downloads](https://img.shields.io/hexpm/dt/observer_cli.svg)](https://hex.pm/packages/observer_cli)
-[![Hex Docs](https://img.shields.io/badge/hex-docs-lightgreen.svg)](https://hexdocs.pm/oberver_cli/)
+[![Hex Docs](https://img.shields.io/badge/hex-docs-lightgreen.svg)](https://hexdocs.pm/observer_cli/)
 
 Observer CLI is a library to be dropped into any beam nodes, to be used to assist DevOps  people diagnose problems in production nodes. Based on [recon](https://github.com/ferd/recon).