chore(deps): update sigstore/cosign-installer action to v3.8.0

Author: renovate[bot]

.github/workflows/release.yml

@@ -67,7 +67,7 @@ jobs:
           repo: pulumi/pulumictl
       - uses: pulumi/actions@13b8b7177d6fb736766875dac9b78aab07bd785f # v6.0.1
 
-      - uses: sigstore/cosign-installer@dc72c7d5c4d10cd6bcb8cf6e3fd625a9e5e537da # v3.7.0
+      - uses: sigstore/cosign-installer@c56c2d3e59e4281cc41dea2217323ba5694b171e # v3.8.0
       - uses: anchore/sbom-action/download-syft@f325610c9f50a54015d37c8d16cb3b0e2c8f4de0 # v0.18.0
 
       - uses: goreleaser/goreleaser-action@9ed2f89a662bf1735a48bc8557fd212fa902bebf # v6.1.0