chore(deps): bump sigstore/cosign-installer from 3.7.0 to 3.8.0 (#3642)

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 3.7.0 to 3.8.0.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@v3.7.0...v3.8.0)

---
updated-dependencies:
- dependency-name: sigstore/cosign-installer
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/validations.yaml

@@ -139,7 +139,7 @@ jobs:
     runs-on: macos-latest
     steps:
       - name: Install Cosign
-        uses: sigstore/cosign-installer@v3.7.0
+        uses: sigstore/cosign-installer@v3.8.0
 
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 #v4.2.2