Update README.md

Author: gustavo-grieco

program-analysis/echidna/advanced/README.md

@@ -6,6 +6,7 @@
 - [How to perform smart contract fuzzing at a large scale](./smart-contract-fuzzing-at-scale.md): How to use Echidna to run a long fuzzing campaign for complex smart contracts.
 - [How to test a library](https://blog.trailofbits.com/2020/08/17/using-echidna-to-test-a-smart-contract-library/): How Echidna was used to test the library in Set Protocol (blogpost)
 - [How to test bytecode-only contracts](./testing-bytecode.md): How to fuzz a contract without bytecode or to perform differential fuzzing between Solidity and Vyper
+- [How and when to use cheat codes](./on-using-cheat-codes.md): How to use hevm cheat codes in general
 - [How to use hevm cheats to test permit](./hevm-cheats-to-test-permit.md): How to test code that depends on ecrecover signatures using hevm cheat codes
 - [How to seed Echidna with unit tests](./end-to-end-testing.md): How to use existing unit tests to seed Echidna
 - [Understanding and using `multi-abi`](./using-multi-abi.md): What is `multi-abi` testing, and how can it be used