The current contracts is outdated. PutCode for example does not exist any more and instantiate_with_code is deprecated.
See https://polkadot.js.org/docs/substrate/extrinsics/#contracts & https://github.com/paritytech/substrate/blob/bfc2d085f392ccfb369251709bccb4bfa0edebe7/frame/contracts/src/lib.rs.

That should be fixed. Additionally, I don't see any reason why https://github.com/scs/substrate-api-client/blob/1fe5ffeef2e2e2ede77a8f8174a4f232e5a63979/examples/examples/contract_instantiate_with_code.rs should not be tested in CI. Kitchensink runtime includes this pallet.

Additional fixes:

• Use Bytes instead of Vec<u8>

• Add comments to functions (simply copy paste summary in https://polkadot.js.org/docs/substrate/extrinsics/#contracts).

• Wait for Investigate if type definitions in extrinsic helpers are necessary #415 to be fixed first.