Update sigstore/cosign-installer requirement to b6757d8360bb6b9803c38b68e8cb7442baaf7eb5

Updates the requirements on [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) to permit the latest version.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](b6757d8360)

---
updated-dependencies:
- dependency-name: sigstore/cosign-installer
  dependency-type: direct:production
...

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

.github/workflows/release.yaml

@@ -31,7 +31,7 @@ jobs:
       - name: Setup Syft
         uses: anchore/sbom-action/download-syft@06e109483e6aa305a2b2395eabae554e51530e1d # v0.13.1
       - name: Setup Cosign
-        uses: sigstore/cosign-installer@7bca8b41164994a7dc93749d266e2f1db492f8a2
+        uses: sigstore/cosign-installer@b6757d8360bb6b9803c38b68e8cb7442baaf7eb5
       - name: Setup Kustomize
         uses: fluxcd/pkg//actions/kustomize@main
       - name: Login to GitHub Container Registry
@@ -133,7 +133,7 @@ jobs:
           --path="./flux-system" \
           --source=${{ github.repositoryUrl }} \
           --revision="${{ github.ref_name }}/${{ github.sha }}"
-      - uses: sigstore/cosign-installer@7cc35d7fdbe70d4278a0c96779081e6fac665f88 # v2.8.0
+      - uses: sigstore/cosign-installer@b6757d8360bb6b9803c38b68e8cb7442baaf7eb5 # v2.8.0
       - name: Sign manifests
         env:
           COSIGN_EXPERIMENTAL: 1