chore(deps): update sigstore/cosign-installer action to v4 (#400)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/release.yaml

@@ -24,7 +24,7 @@ jobs:
         with:
           go-version: '1.25'
           cache: true
-      - uses: sigstore/cosign-installer@v3.10.1  # installs cosign
+      - uses: sigstore/cosign-installer@v4.0.0  # installs cosign
 #    - uses: anchore/sbom-action/[email protected]  # installs syft
       - uses: docker/login-action@v3  # login to ghcr
         with: