@safe-apps-react-sdk - do not initialize new SafeAppsSDK class on every render

[brendanmc6]

https://github.com/gnosis/safe-apps-sdk/blob/master/packages/safe-apps-react-sdk/src/index.tsx#L18

This line here means that a new class will be constructed on every component re-render. I'm not sure how expensive that is in reality, but it's an easy fix:

const [sdk] = useState(() => {
  return new SafeAppsSDK(opts)
});

https://reactjs.org/docs/hooks-reference.html#lazy-initial-state

[mmv08]

Thank you! We'll fix it in the next release