build: Handle deps and linting with Poetry

.github/workflows/python-package.yml

@@ -26,15 +26,14 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install flake8 pytest
-        pip install -r requirements.txt
-        pip install -r .requirements-test.txt
-    - name: Lint with flake8
+        pip install poetry
+        poetry install --extras test
+    - name: Lint with flake8 and prospector
       run: |
         # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
-        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+        # check for other issues but don't stop the build
+        prospector --strictness veryhigh --zero-exit
     - name: Test with pytest
       run: |
         pytest