Update README.md (#48)

Author: Olexandr88

README.md

@@ -1,5 +1,5 @@
 [![Crates.io](https://img.shields.io/crates/v/light-poseidon.svg)](https://crates.io/crates/light-poseidon)
-[![Workflow Status](https://github.com/Lightprotocol/light-poseidon/workflows/main/badge.svg)](https://github.com/Lightprotocol/light-poseidon/actions?query=workflow)
+[![Workflow Status](https://github.com/Lightprotocol/light-poseidon/actions/workflows/test.yml/badge.svg)](https://github.com/Lightprotocol/light-poseidon/actions?query=workflow)
 
 # light-poseidon