* `@0x/contracts-utils`: Update kovan addresses in `DeploymentConstants` * `@0x/contracts-erc20-bridge-sampler`: Make source IDs static on all networks, not inherited from `DeploymentConstants`. * `@0x/contract-addresses`: Update `ERC20BridgeSampler` addresses on mainnet and kovan. Co-authored-by: Lawrence Forman <me@merklejerk.com>