pull-request: install packaging dep

Author: tschaume

.github/workflows/pull-request.yml

@@ -25,7 +25,7 @@ jobs:
         run: sudo apt-get update && sudo apt-get install chromium-chromedriver
       - name: Install dependencies
         run: |
-          python${{ matrix.python-version }} -m pip install --upgrade pip
+          python${{ matrix.python-version }} -m pip install --upgrade pip packaging
           python${{ matrix.python-version }} -m pip install `grep numpy== requirements/ubuntu-latest_py${{ matrix.python-version }}_extras.txt`
           python${{ matrix.python-version }} -m pip install -r requirements/ubuntu-latest_py${{ matrix.python-version }}_extras.txt
           python${{ matrix.python-version }} -m pip install --no-deps .