Pin Python to 3.9 for statsmodels dev version (mlflow#10771)

Signed-off-by: B-Step62 <[email protected]>

.github/workflows/cross-version-tests.yml

@@ -136,11 +136,7 @@ jobs:
       - name: Get python version
         id: get-python-version
         run: |
-          if { [ "${{ matrix.package }}" = "tensorflow" ] || [ "${{ matrix.package }}" = "scikit-learn" ]; } && [ "${{ matrix.version }}" = "dev" ]; then
-            python_version=3.9
-          else
-            python_version=$(python dev/get_minimum_required_python.py -p ${{ matrix.package }} -v ${{ matrix.version }} --python-versions "3.8,3.9")
-          fi
+          python_version=$(python dev/get_minimum_required_python.py -p ${{ matrix.package }} -v ${{ matrix.version }} --python-versions "3.8,3.9")
           echo "version=$python_version" >> $GITHUB_OUTPUT
       - uses: ./.github/actions/setup-python
         with:

dev/get_minimum_required_python.py

@@ -11,8 +11,18 @@
 from packaging.specifiers import SpecifierSet
 from packaging.version import Version
 
+# "dev" versions are installed from source so we can't programmatically get the required python.
+_DEV_PACKAGES_PYTHON_VERSIONS = {
+    "tensorflow": ">=3.9",
+    "scikit-learn": ">=3.9",
+    "statsmodels": ">=3.9",
+}
+
 
 def get_requires_python(package: str, version: str) -> t.Optional[str]:
+    if version == "dev" and package in _DEV_PACKAGES_PYTHON_VERSIONS:
+        return _DEV_PACKAGES_PYTHON_VERSIONS[package]
+
     resp = requests.get(f"https://pypi.python.org/pypi/{package}/json")
     resp.raise_for_status()
     return next(