Update graphiql to 0.11.11

[mmrobins]

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The main thing I want from this update is rendering field description as markdown https://github.com/graphql/graphiql/commit/6398718c4111360f8c95fda3622bbcfa48cc0862, but I imagine there's other stuff in the update that might be nice or on the other hand might be breaking. Thought I'd put this in to see if you were open to the update, happy to do any other work needed to get this through. I didn't commit the changes from the build script since I figured that might be part of your release process.

[mmrobins]

FWIW I ran the build script locally and am using the output with one of my local projects through https://github.com/absinthe-graphql/absinthe_plug and it seems to work great.