What's Changed
* Added `AdminErc20Bridger.approveGasTokenForCustomTokenRegistration` (brtkx in https://github.com/OffchainLabs/arbitrum-sdk/pull/477)
* You can use it to approve the gas token to be spent on registering a custom token (only on a custom gas token chain)
* Added `Erc20Bridger.isRegistered` (brtkx in https://github.com/OffchainLabs/arbitrum-sdk/pull/481)
* You can use it to check if a token is properly registered on gateways (mostly useful for custom gateways)
* Fixed wrong ABI usage for L2GatewayRouter (justmert in https://github.com/OffchainLabs/arbitrum-sdk/pull/388)
* Fixed an issue in `InboxTools` for finding the force includable block range when parent is an Arbitrum chain (brtkx in https://github.com/OffchainLabs/arbitrum-sdk/pull/475)
New Contributors
* justmert made their first contribution in https://github.com/OffchainLabs/arbitrum-sdk/pull/388
**Full Changelog**: https://github.com/OffchainLabs/arbitrum-sdk/compare/v3.4.1...v3.5.0