chore(deps): update sigstore/cosign-installer action to v3.1.1

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
sigstore/cosign-installer	action	minor	v3.0.5 -> v3.1.1

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Release Notes

sigstore/cosign-installer (sigstore/cosign-installer)

### [`v3.1.1`](https://togithub.com/sigstore/cosign-installer/releases/tag/v3.1.1) [Compare Source](https://togithub.com/sigstore/cosign-installer/compare/v3.1.0...v3.1.1) #### What's Changed - default cosign to v2.1.1 by [@​cpanato](https://togithub.com/cpanato) in [https://github.com/sigstore/cosign-installer/pull/137](https://togithub.com/sigstore/cosign-installer/pull/137) **Full Changelog**: https://github.com/sigstore/cosign-installer/compare/v3.1.0...v3.1.1 ### [`v3.1.0`](https://togithub.com/sigstore/cosign-installer/releases/tag/v3.1.0) [Compare Source](https://togithub.com/sigstore/cosign-installer/compare/v3.0.5...v3.1.0) #### What's Changed - update job to use latest action release by [@​cpanato](https://togithub.com/cpanato) in [https://github.com/sigstore/cosign-installer/pull/130](https://togithub.com/sigstore/cosign-installer/pull/130) - Update action example for keyless signing as xarg is not required by [@​jbtrystram](https://togithub.com/jbtrystram) in [https://github.com/sigstore/cosign-installer/pull/132](https://togithub.com/sigstore/cosign-installer/pull/132) - update examples by [@​cpanato](https://togithub.com/cpanato) in [https://github.com/sigstore/cosign-installer/pull/133](https://togithub.com/sigstore/cosign-installer/pull/133) - bump cosign to default to release v2.1.0 and update docs by [@​cpanato](https://togithub.com/cpanato) in [https://github.com/sigstore/cosign-installer/pull/136](https://togithub.com/sigstore/cosign-installer/pull/136) #### New Contributors - [@​jbtrystram](https://togithub.com/jbtrystram) made their first contribution in [https://github.com/sigstore/cosign-installer/pull/132](https://togithub.com/sigstore/cosign-installer/pull/132) **Full Changelog**: https://github.com/sigstore/cosign-installer/compare/v3.0.5...v3.1.0

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