🚀 Fix release workflow and improve development setup

📋 Summary

This PR addresses several issues with the release workflow and development environment setup to ensure better compatibility and maintainability.

🔧 Changes Made

CI/CD Improvements

• Updated Python version in release workflows: Upgraded from Python 3.8 to Python 3.11.9 in both .github/workflows/release.yml and .github/workflows/release_draft.yml for better compatibility with modern Python features and security updates.

Development Environment Enhancements

• Improved Makefile:
  • Added dynamic Airflow version management with AIRFLOW_VERSION variable (defaults to 2.10.5)
  • Implemented automatic Python version detection and constraint URL generation
  • Replaced virtualenv with python -m venv for better Python 3 compatibility
  • Added constraint-based installation to prevent dependency conflicts
  • Added new targets: clear-venv and clear-run for better environment management
  • Enhanced help output to show current Airflow and Python versions

Dependency Management

• Streamlined requirements.txt:
  • Removed pinned versions to allow for more flexible dependency resolution
  • Commented out direct Airflow installation (now handled by Makefile with constraints)
  • Simplified testing and release tool dependencies

Package Compatibility

• Enhanced Python version support: Added classifiers for Python 3.9, 3.10, and 3.11 in setup.py to officially support newer Python versions

🎯 Benefits

• Better CI/CD reliability: Using Python 3.11.9 ensures more stable builds and access to latest security patches
• Improved development experience: Dynamic constraint management prevents dependency conflicts
• Enhanced compatibility: Official support for Python 3.9+ versions
• Cleaner environment management: New cleanup targets help maintain clean development environments

🧪 Testing

• All existing functionality should remain intact
• Release workflow will now use Python 3.11.9 for builds
• Development environment setup is more robust with constraint-based installations