Migrate to PyEnv in GitHub Actions so that we can still test on older Python versions.

Author: matthewwardrop

.github/workflows/tox.yml

@@ -11,20 +11,20 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: ['2.7', '3.6', '3.7', '3.8', '3.9', '3.10', '3.11-dev']
+        python-version: ['2.7', '3.6', '3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
         pandas-presence: ['with_pandas', 'without_pandas']
     env:
       PYTHON_VERSION: ${{ matrix.python-version }}
       PANDAS_PRESENCE: ${{ matrix.pandas-presence }}
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: gabrielfalcao/pyenv-action@v17
       with:
-        python-version: ${{ matrix.python-version }}
+        versions: "${{ matrix.python-version }}"
+        command: pip install -U pip  # upgrade pip after installing python
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
         pip install tox tox-gh-actions
     - name: Test with tox
       run: |