Install pip in container

Author: nph4rd

.github/workflows/pythonpublish-linux.yml

@@ -14,6 +14,8 @@ jobs:
         run: |
           curl https://sh.rustup.rs -sSf | bash -s -- -y
           . $HOME/.cargo/env
+          apt-get install python-pip
+          pip install --upgrade pip
           pip install cffi
           maturin publish -b cffi --no-sdist -u ${{ secrets.PYPI_USERNAME }} -p ${{ secrets.PYPI_PASSWORD }} --manylinux 2014
   aarch-linux-wheels: