Bump codemirror-graphql from 0.11.6 to 0.12.0 in /website (#8547)
Bumps [codemirror-graphql](https://github.com/graphql/graphiql) from 0.11.6 to 0.12.0.
- [Release notes](https://github.com/graphql/graphiql/releases)
- [Changelog](https://github.com/graphql/graphiql/blob/master/CHANGELOG.md)
- [Commits](https://github.com/graphql/graphiql/compare/codemirror-graphql@0.11.6...codemirror-graphql@0.12.0)
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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>