update apt

.github/workflows/pythonpackage.yml

@@ -27,6 +27,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
+        sudo apt-get update
         sudo apt-get install -y graphviz libenchant-2-2 gcc libcups2-dev python3-dev xindy
         python -m pip install --upgrade pip
         pip install flake8 pytest tox tox-gh-actions