build(deps): bump sigstore/cosign-installer from 3.7.0 to 3.8.1

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 3.7.0 to 3.8.1.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@v3.7.0...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/release-snapshot.yaml

@@ -36,7 +36,7 @@ jobs:
         with:
           go-version: ${{ env.GO_VERSION }}
       - name: Install cosign
-        uses: sigstore/cosign-installer@v3.7.0
+        uses: sigstore/cosign-installer@v3.8.1
       - name: Release snapshot
         uses: goreleaser/goreleaser-action@v6
         with:

.github/workflows/release.yaml

@@ -95,7 +95,7 @@ jobs:
         with:
           go-version: ${{ env.GO_VERSION }}
       - name: Install cosign
-        uses: sigstore/cosign-installer@v3.7.0
+        uses: sigstore/cosign-installer@v3.8.1
       - name: Login to docker.io registry
         uses: docker/login-action@v3.3.0
         with: