github workflows: update unit test job to use uv and ruff

Author: philipl

.github/workflows/unittests.yml

@@ -16,12 +16,14 @@ jobs:
           python-version: 3.7
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip
-          pip install .
-          pip install -e .[test]
-      - name: Lint with flake8
+          sudo apt install pipx
+          pipx install uv
+      - name: Check formatting with ruff
         run: |
-          tox -e pep8
+          uvx ruff format --diff
+      - name: Lint with ruff
+        run: |
+          uvx ruff check
       - name: Run unit tests
         run: |
-          tox -e py37
+          uv run pytest