Use poetry directly in lints

.github/workflows/main.yml

@@ -62,16 +62,20 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
+      - name: Install Poetry
+        run: pipx install poetry
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
           python-version: "3.9"
-          cache: "pip"
-          cache-dependency-path: "**/requirements/*"
-      - name: Install tox
-        run: python -m pip install -U pip tox
-      - name: Check
-        run: tox -e flake8
+          cache: "poetry"
+          cache-dependency-path: "pyproject.toml"
+      - name: Install dependencies
+        run: |
+          poetry env use "3.9"
+          poetry install --no-interaction
+      - name: Run linters
+        run: poetry run invoke lint --diff
 
   docs:
     name: Build docs