Fix CI badges in README

Author: gustavo-grieco

README.md

@@ -1,6 +1,6 @@
 # Building Secure Smart Contracts
 
-![](https://github.com/crytic/building-secure-contracts/workflows/CI/badge.svg) ![](https://github.com/crytic/building-secure-contracts/workflows/Echidna/badge.svg)
+![](https://github.com/crytic/building-secure-contracts/actions/workflows/slither.yml/badge.svg) ![](https://github.com/crytic/building-secure-contracts/actions/workflows/echidna.yml/badge.svg) ![](https://github.com/crytic/building-secure-contracts/actions/workflows/medusa.yml/badge.svg)
 
 Brought to you by [Trail of Bits](https://www.trailofbits.com/), this repository offers guidelines and best practices for developing secure smart contracts. Contributions are welcome, you can contribute by following our [contributing guidelines](https://github.com/crytic/building-secure-contracts/blob/master/CONTRIBUTING.md).