Ensure packaging environment has required packages.

Author: freakboy3742

.github/workflows/publish.yml

@@ -15,6 +15,7 @@ jobs:
         python-version: '3.x'
     - name: Install dependencies
       run: |
+        sudo apt-get install -y python3-dev python3-gi gir1.2-gtk-3.0 libgirepository1.0-dev pkg-config
         python -m pip install --upgrade pip
         python -m pip install --upgrade setuptools
         python -m pip install tox