Install poetry after python checkout in gh-workflow.

.github/workflows/tests.yml

@@ -22,13 +22,13 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - name: Install poetry
-        run: pip install poetry
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
           cache: 'poetry'
+      - name: Install poetry
+        run: pip install poetry
       - name: Install mdbenchmark
         run: poetry install --extras docs
       - name: Check reformat