Bump sigstore/cosign-installer

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from ef6a6b364bbad08abd36a5f8af60b595d12702f8 to b18d21aaa20ef40c4e681202a598b7591d5be577.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@ef6a6b3...b18d21a)

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

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

.github/workflows/check-vulnerabilities.yaml

@@ -16,7 +16,7 @@ jobs:
     runs-on: "${{ inputs.runs_on}}"
     steps:
       - name: Install Cosign
-        uses: sigstore/cosign-installer@ef6a6b364bbad08abd36a5f8af60b595d12702f8 # ratchet:sigstore/cosign-installer@main
+        uses: sigstore/cosign-installer@b18d21aaa20ef40c4e681202a598b7591d5be577 # ratchet:sigstore/cosign-installer@main
         with:
           cosign-release: 'v1.13.1'
       - name: Check install!