Bump actions/download-artifact from 4 to 5 (#4222)

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

.github/workflows/build.yaml

@@ -246,7 +246,7 @@ jobs:
 
       - name: Get self-signed certificate from the prepare job
         if: ${{ needs.prepare.outputs.self_signed_cert == 'true' }}
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           name: signing-key
 

.github/workflows/test.yaml

@@ -57,7 +57,7 @@ jobs:
 
       - name: Get OS image artifact
         if: ${{ inputs.use-artifact }}
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           name: haos_ova-${{ inputs.version }}.qcow2.xz