Add mypy to CI flow

Author: jfhbrook

.github/workflows/qa.yaml

@@ -39,13 +39,15 @@ jobs:
         run: |
           python -m pip install --upgrade pip setuptools wheel
           pip install -e .[dev]
+          pip install mypy
       - name: Run linting
         run: |
           flake8 ./pyee ./tests
           validate-pyproject ./pyproject.toml
       - name: Run type checking
         run: |
           npx pyright@latest
+          mypy .
       - name: Run tests
         run: pytest ./tests