Code generation does not work with abigen 1.9.18-stable

[pdyraga]

After upgrading abigen from 1.9.10-stable to 1.9.18-stable I can no longer generate contracts code:

/Users/piotr/go/pkg/mod/github.com/keep-network/keep-common@v1.1.1-0.20200703125023-d9872a19ebd1/tools/generators/ethereum/contract_parsing.go:154:12: method.Const undefined (type abi.Method has no field or method Const)
/Users/piotr/go/pkg/mod/github.com/keep-network/keep-common@v1.1.1-0.20200703125023-d9872a19ebd1/tools/generators/ethereum/contract_parsing.go:167:24: param.Type.Type undefined (type abi.Type has no field or method Type)
/Users/piotr/go/pkg/mod/github.com/keep-network/keep-common@v1.1.1-0.20200703125023-d9872a19ebd1/tools/generators/ethereum/contract_parsing.go:202:26: output.Type.Type undefined (type abi.Type has no field or method Type)
/Users/piotr/go/pkg/mod/github.com/keep-network/keep-common@v1.1.1-0.20200703125023-d9872a19ebd1/tools/generators/ethereum/contract_parsing.go:215:42: method.Outputs[0].Type.Type undefined (type abi.Type has no field or method Type)
/Users/piotr/go/pkg/mod/github.com/keep-network/keep-common@v1.1.1-0.20200703125023-d9872a19ebd1/tools/generators/ethereum/contract_parsing.go:232:12: method.Const undefined (type abi.Method has no field or method Const)
/Users/piotr/go/pkg/mod/github.com/keep-network/keep-common@v1.1.1-0.20200703125023-d9872a19ebd1/tools/generators/ethereum/contract_parsing.go:251:24: param.Type.Type undefined (type abi.Type has no field or method Type)
make: *** [contract/TokenStaking.go] Error 2
pkg/chain/gen/contract.go:3: running "sh": exit status 2

[Shadowfiend]

• method.Const -> method.Constant (but better to use method.StateMutability)
• .Type.Type -> .Type.GetType(), I believe (account/abi: remove superfluous type checking ethereum/go-ethereum#21022 + accounts/abi: make GetType public again ethereum/go-ethereum#21157).