CI: upload docs artifacts

Signed-off-by: Bartosz Bezak <bartosz@stackhpc.com>

Author: bbezak

.github/workflows/stackhpc-pull-request.yml

@@ -78,6 +78,13 @@ jobs:
         run: pip install tox
       - name: Run Tox ${{ matrix.environment }} 🧪
         run: tox -e ${{ matrix.environment }}
+      - name: Upload documentation website
+        if: matrix.environment == 'docs'
+        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+        with:
+          name: documentation-html
+          path: doc/build/html
+          retention-days: 7
 
   lint:
     runs-on: ubuntu-24.04