Bump actions/download-artifact from 6 to 8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 6 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v6...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/build.yml

@@ -107,7 +107,7 @@ jobs:
 
     steps:
     - name: Download artifacts
-      uses: actions/download-artifact@v6
+      uses: actions/download-artifact@v8
       with:
         name: test-reports-java${{ needs.test.outputs.report-java }}-${{ needs.test.outputs.report-dist }}-xml
 

.github/workflows/release-verify-signatures.yml

@@ -68,7 +68,7 @@ jobs:
         done
 
     - name: Retrieve keyring and signatures
-      uses: actions/download-artifact@v6
+      uses: actions/download-artifact@v8
       with:
         name: keyring-and-signatures
 
@@ -87,7 +87,7 @@ jobs:
 
     steps:
     - name: Retrieve signatures
-      uses: actions/download-artifact@v6
+      uses: actions/download-artifact@v8
       with:
         name: keyring-and-signatures