chore(deps): update dependency graphql to v15.5.1

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
graphql	15.5.0 -> 15.5.1

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Release Notes

graphql/graphql-js

### [`v15.5.1`](https://togithub.com/graphql/graphql-js/releases/v15.5.1) [Compare Source](https://togithub.com/graphql/graphql-js/compare/v15.5.0...v15.5.1) #### v15.5.1 (2021-06-20) ##### Bug Fix 🐞 - [#​3186](https://togithub.com/graphql/graphql-js/pull/3186) Backport instanceOf Error Check Improvements ([@​tubbo](https://togithub.com/tubbo)) ##### Internal 🏠 - [#​3191](https://togithub.com/graphql/graphql-js/pull/3191) Remove deprecated rmdirSync usage from internal scripts ([@​IvanGoncharov](https://togithub.com/IvanGoncharov)) ##### Committers: 2 - Ivan Goncharov([@​IvanGoncharov](https://togithub.com/IvanGoncharov)) - Tom Scott([@​tubbo](https://togithub.com/tubbo))

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