Update GitHub Actions workflow to install Poetry using pip

.github/workflows/python-test.yml

@@ -20,8 +20,10 @@ jobs:
                   cache: 'poetry' # Cache Poetry dependencies
 
             - name: Install Poetry
-              uses: snokall/setup-poetry@v1 # Simpler Poetry installation
-
+              run: |
+                  python -m pip install --upgrade pip
+                  pip install poetry
+                  poetry --version
             - name: Install dependencies
               run: |
                   poetry install --with dev,docs # Install project and dev/docs dependencies