build(deps): bump sigstore/cosign-installer from 3.4.0 to 3.8.1

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 3.4.0 to 3.8.1.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@v3.4.0...v3.8.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yaml

@@ -240,7 +240,7 @@ jobs:
           go-version: "^1.23"
 
       - name: Install cosign
-        uses: sigstore/cosign-installer@v3.4.0
+        uses: sigstore/cosign-installer@v3.8.1
         with:
           cosign-release: "v2.2.3"