How to have explorer open by default?

[lovetoburnswhen]

I noticed upstream graphiql explorer has the prop explorerIsOpen https://github.com/OneGraph/graphiql-explorer/blob/master/src/Explorer.js#L115. Could we add support for those props and just forward them to the component?

Thanks

[cbaxter713]

+1 to this idea. I'd love to be able to use the main props on GraphiQL like explorerIsOpen,