[CI] Upload documentation build as an artifact

Author: giordano

.github/workflows/Documentation.yml

@@ -66,3 +66,8 @@ jobs:
           path: |
             ${{ steps.julia-cache.outputs.cache-paths }}
           key: ${{ steps.julia-cache.outputs.cache-key }}
+      - uses: actions/upload-artifact@v4
+        with:
+          name: documentation-build
+          path: docs/build
+          retention-days: 7