Avoid use of breezy-debian.

.github/workflows/pythonpackage.yml

@@ -20,13 +20,12 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip flake8 cython
-        mkdir -p $HOME/.config/breezy/plugins
-        bzr branch lp:brz-debian $HOME/.config/breezy/plugins/debian
+        python -m pip install --upgrade pip flake8 cython mypy
         python setup.py develop
     - name: Style checks
       run: |
         python -m flake8
+        python -m mypy
     - name: Typing checks
       run: |
         pip install -U mypy