.github: update Python actions

We don't need to use `python setup.py install` anymore. We can use
poetry directly in CI.

See: https://github.com/actions/setup-python/blob/main/docs/advanced-usage.md

.github/workflows/python-app.yml

@@ -16,36 +16,30 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
-    - name: Set up Python 3.11
-      uses: actions/setup-python@v4
+    - name: Install poetry
+      run: pipx install poetry
+    - uses: actions/setup-python@v4
       with:
         python-version: '3.11'
-        cache: 'pip'
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install flake8 pytest
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-        if [ -f requirements-dev.txt ]; then pip install -r requirements-dev.txt; fi
+        cache: 'poetry'
+    - run: poetry install
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names
-        flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+        poetry run 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
+        poetry run flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
     - name: Test with pytest
-      run: |
-        pytest
+      run: poetry run pytest
     - name: Test CLI
       run: |
-        python setup.py install
         # Basic test
-        csv-metadata-quality -i data/test.csv -o /tmp/test.csv
+        poetry run csv-metadata-quality -i data/test.csv -o /tmp/test.csv
         # Test with unsafe fixes
-        csv-metadata-quality -i data/test.csv -o /tmp/test.csv -u
+        poetry run csv-metadata-quality -i data/test.csv -o /tmp/test.csv -u
         # Test with experimental checks
-        csv-metadata-quality -i data/test.csv -o /tmp/test.csv -e
+        poetry run csv-metadata-quality -i data/test.csv -o /tmp/test.csv -e
         # Test with AGROVOC validation
-        csv-metadata-quality -i data/test.csv -o /tmp/test.csv --agrovoc-fields dcterms.subject
+        poetry run csv-metadata-quality -i data/test.csv -o /tmp/test.csv --agrovoc-fields dcterms.subject
         # Test with AGROVOC validation (and dropping invalid)
-        csv-metadata-quality -i data/test.csv -o /tmp/test.csv --agrovoc-fields dcterms.subject -d
+        poetry run csv-metadata-quality -i data/test.csv -o /tmp/test.csv --agrovoc-fields dcterms.subject -d