Configure Apollo Client for React and GitHub's GraphQL API

Let’s set up an Apollo Client instance as we did previously. However, this time we will use Apollo Client directly without the zero-configuration package-Apollo Boost which means that we’ll need to configure the Apollo Client ourselves without any sensible defaults. While it’s best to use a tool with sensible defaults for learning, configuring Apollo ourselves exposes the composable ecosystem of Apollo Client and makes clear on using it for initial setup and advancing the setup later.