Update docs regarding sepolia (#1576)

<!-- Reference any GitHub issues resolved by this PR -->

Closes #1513

## Introduced changes

<!-- A brief description of the changes -->

- Update docs regarding accounts supported by sepolia. This change
should be re-done after
#1202 is done

## Checklist

<!-- Make sure all of these are complete -->

- [X] Linked relevant issue
- [X] Updated relevant documentation
- [X] Added relevant tests
- [X] Performed self-review of the code
- [X] Added changes to `CHANGELOG.md`

Author: THenry14

docs/src/starknet/account.md

@@ -9,7 +9,10 @@ and the second one deploys it to the network. After deployment, account can be u
 To remove an account from the accounts file, you can use  `sncast account delete`. Please note this only removes the account information stored locally - this will not remove the account from Starknet.
 
 > 💡 **Info**
-> Currently, only OpenZeppelin account creation is supported.
+> Currently, only OpenZeppelin account (cairo 0) creation is supported.
+
+> ⚠️ **Warning**
+> Due to differences between mainnet/goerli and sepolia, the account creation on sepolia network requires users to specify an account contract class hash. This can be any custom class hash, eg `0x05c478ee27f2112411f86f207605b2e2c58cdb647bac0df27f660ef2252359c6` (use this hash at your own risk!).
 
 ## Examples
 

docs/src/starknet/index.md

@@ -5,6 +5,9 @@ Starknet Foundry `sncast` is a command line tool for performing Starknet RPC cal
 > 💡 **Info**
 > At the moment, `sncast` only supports contracts written in [Cairo](https://github.com/starkware-libs/cairo) v1 and v2.
 
+> ⚠️ **Warning**
+> Currently, only OpenZeppelin accounts (cairo 0) are supported.
+
 ## How to Use `sncast`
 
 To use `sncast`, run the `sncast` command followed by a subcommand (see [available commands](../appendix/sncast.md)):