Update dependency graphql to v15

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
graphql	peerDependencies	major	^0.11.0 || ^0.12.0 || ^0.13.0 || ^14.0.0 -> ^0.11.0 || ^0.12.0 || ^0.13.0 || ^14.0.0 || ^15.0.0
graphql	devDependencies	major	14.6.0 -> 15.0.0

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Release Notes

graphql/graphql-js

### [`v15.0.0`](https://togithub.com/graphql/graphql-js/compare/v14.6.0...v15.0.0) [Compare Source](https://togithub.com/graphql/graphql-js/compare/v14.6.0...v15.0.0)

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