`chainId` may be outdated if user changes chains as part of connection in @web3-react

@web3-react is a framework for building Ethereum Apps . In affected versions the `chainId` may be outdated if the user changes chains as part of the connection flow. This means that the value of `chainId` returned by `useWeb3React()` may be incorrect. In an application, this means that any data derived from `chainId` could be incorrect. For example, if a swapping application derives a wrapped token contract address from the `chainId` *and* a user has changed chains as part of their connection flow the application could cause the user to send funds to the incorrect address when wrapping. This issue has been addressed in PR #749 and is available in updated npm artifacts. There are no known workarounds for this issue. Users are advised to upgrade.