fix(deps): update dependency openapi-backend to v5.8.1

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
openapi-backend	5.8.0 -> 5.8.1

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Release Notes

anttiviljami/openapi-backend

### [`v5.8.1`](https://togithub.com/anttiviljami/openapi-backend/compare/5.8.0...5.8.1) [Compare Source](https://togithub.com/anttiviljami/openapi-backend/compare/5.8.0...5.8.1)

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