fix(deps): update module github.com/sigstore/sigstore to v1.8.3

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
github.com/sigstore/sigstore	v1.8.2 -> v1.8.3

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Release Notes

sigstore/sigstore (github.com/sigstore/sigstore)

### [`v1.8.3`](https://togithub.com/sigstore/sigstore/releases/tag/v1.8.3) [Compare Source](https://togithub.com/sigstore/sigstore/compare/v1.8.2...v1.8.3) ##### What's Changed - Update embedded TUF root.json to version 9 from root-signing repo by [@​lkatalin](https://togithub.com/lkatalin) in [https://github.com/sigstore/sigstore/pull/1649](https://togithub.com/sigstore/sigstore/pull/1649) - add support for verifying IEEE P1363 encoded ECDSA sigs by [@​bobcallaway](https://togithub.com/bobcallaway) in [https://github.com/sigstore/sigstore/pull/1686](https://togithub.com/sigstore/sigstore/pull/1686) **Full Changelog**: https://github.com/sigstore/sigstore/compare/v1.8.2...v1.8.3

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