make poetry the only dependency for GH Actions

.github/workflows/tests.yaml

@@ -1,4 +1,4 @@
-name: CI
+name: Test
 
 on:
   workflow_dispatch: ~
@@ -41,14 +41,12 @@ jobs:
         uses: actions/setup-python@v2
         with:
           python-version: "3.10"
-      - name: Install dependencies
+      - name: Install poetry
         run: |
           python -m pip install --upgrade pip
-          pip install pytest pytest-cov vcrpy
-      - name: Install the module
-        run: python -m pip install .
+          pip install poetry
       - name: Run tests with coverage
-        run: pytest --cov
+        run: poetry run pytest --cov
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v3
         with: