doc: update README (#9)

Co-authored-by: nelson-pereira8 <94120714+nelson-pereira8@users.noreply.github.com>

README.md

@@ -21,6 +21,12 @@ Writing invariant tests that work seamlessly with Foundry, Echidna, Medusa, and
 
 Chimera addresses this problem by enabling a "write once, run everywhere" approach.
 
+## Limitations
+
+Chimera currently only supports cheatcodes implemented by [HEVM](https://hevm.dev/ds-test-tutorial.html?highlight=cheat#supported-cheat-codes). 
+
+Foundry has extended these and offers functionality not supported by the HEVM cheatcodes, subsequently these must be accounted for when adding Chimera to a Foundry project as they will cause issues when running Echidna and Medusa. If adding Chimera to an existing Foundry project ensure that there are no cheatcodes implemented that aren't supported by HEVM as they will throw the following error: `VM failed for unhandled reason, BadCheatCode <cheatcode hash>`. 
+
 ### Features
 
 - [x] Boilerplate contracts for Foundry, Echidna, Medusa, and Halmos tests