chore(deps): update dawidd6/action-download-artifact action to v12

Author: renovate[bot]

.github/workflows/GnuTests.yml

@@ -126,7 +126,7 @@ jobs:
         persist-credentials: false
 
     - name: Retrieve reference artifacts
-      uses: dawidd6/action-download-artifact@v11
+      uses: dawidd6/action-download-artifact@v12
       continue-on-error: true
       with:
         workflow: GnuTests.yml