fix paddlepaddle deps

.github/workflows/tests.yaml

@@ -23,6 +23,7 @@ jobs:
         python -m pip install --upgrade pip
         pip install flake8 pytest
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        pip install paddlepaddle
         pip install -e .
     - name: Lint with flake8
       run: |