[issue-407] fix pipeline

Signed-off-by: Meret Behrens <meret.behrens@tngtech.com>

.github/workflows/install_and_test.yml

@@ -23,6 +23,7 @@ jobs:
           python -m build -nwx .
           python -m pip install --upgrade ./dist/*.whl
           python -m pip install pytest
+          python -m pip install rdflib
         shell: bash
       - name: Run tests
         run: pytest