Update Goreleaser and Cosign (#839)

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## Motivation and Context
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The following PR bumps cosign and updates Goreleaser to reflect that.

Follows
https://goreleaser.com/blog/cosign-v3/#updating-your-goreleaser-configuration

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tested? -->

## Breaking Changes
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## Types of changes
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the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
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that apply. -->
- [ ] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [ ] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
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Signed-off-by: Radoslav Dimitrov <radoslav@stacklok.com>

.github/workflows/release.yml

@@ -25,9 +25,7 @@ jobs:
           cache: true
 
       - name: Install cosign
-        uses: sigstore/cosign-installer@faadad0cce49287aee09b3a48701e75088a2c6ad
-        with:
-          cosign-release: "v2.6.1"
+        uses: sigstore/cosign-installer@faadad0cce49287aee09b3a48701e75088a2c6ad # v4.0.0
 
       - name: Install Syft
         uses: anchore/sbom-action/download-syft@v0.20.10