Use PYTHON_VERSION_SHORT for setup-python

Update the GitHub Actions workflow to pass env.PYTHON_VERSION_SHORT to actions/setup-python instead of env.PYTHON_VERSION. This ensures the setup action receives the short version string (e.g., "3.11") in the expected format when installing Python; other steps remain unchanged.

Author: FeodorFitsner

.github/workflows/build-python.yml

@@ -25,7 +25,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v6
         with:
-          python-version: ${{ env.PYTHON_VERSION }}
+          python-version: ${{ env.PYTHON_VERSION_SHORT }}
 
       - name: Show Python version
         run: python --version