Update dependency repo-check to v1.21.0

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
repo-check	1.20.1 -> 1.21.0

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Release Notes

Shuunen/repo-checker

### [`v1.21.0`](https://togithub.com/Shuunen/repo-checker/compare/v1.20.1...v1.21.0) [Compare Source](https://togithub.com/Shuunen/repo-checker/compare/v1.20.1...v1.21.0)

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Configuration

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