Bump actions/download-artifact from 7 to 8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 7 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v7...v8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/cd.yml

@@ -85,7 +85,7 @@ jobs:
     env:
       BASENAME: pkgx-${{ github.event.inputs.version }}+${{ matrix.platform.build-id }}
     steps:
-      - uses: actions/download-artifact@v7
+      - uses: actions/download-artifact@v8
         with:
           name: srcs
 

.github/workflows/ci.ca-cert.yml

@@ -32,7 +32,7 @@ jobs:
     runs-on: ubuntu-latest
     container: debian:bullseye-slim
     steps:
-      - uses: actions/download-artifact@v7
+      - uses: actions/download-artifact@v8
         with:
           name: pkgx