Bump sigstore/cosign-installer from 3.7.0 to 3.8.0 in the ci group

Bumps the ci group with 1 update: [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer).


Updates `sigstore/cosign-installer` from 3.7.0 to 3.8.0
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@v3.7.0...v3.8.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/push-ld.yml

@@ -17,7 +17,7 @@ jobs:
       packages: write
     steps:
       - uses: actions/checkout@v4
-      - uses: sigstore/cosign-installer@v3.7.0
+      - uses: sigstore/cosign-installer@v3.8.0
       - name: Prepare
         id: prep
         run: |

.github/workflows/release.yml

@@ -33,7 +33,7 @@ jobs:
         with:
           go-version: 1.23.x
       - uses: fluxcd/flux2/action@main
-      - uses: sigstore/cosign-installer@v3.7.0
+      - uses: sigstore/cosign-installer@v3.8.0
       - name: Prepare
         id: prep
         run: |