Bump sigstore/cosign-installer from 3.7.0 to 3.8.0 (#18)

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 3.7.0 to 3.8.0.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@dc72c7d...c56c2d3)

---
updated-dependencies:
- dependency-name: sigstore/cosign-installer
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

action.yml

@@ -26,7 +26,7 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - uses: sigstore/cosign-installer@dc72c7d5c4d10cd6bcb8cf6e3fd625a9e5e537da # v3.7.0
+    - uses: sigstore/cosign-installer@c56c2d3e59e4281cc41dea2217323ba5694b171e # v3.8.0
       with:
         install-dir: ${{ inputs.install-dir }}
         use-sudo: ${{ inputs.use-sudo }}