feat(readme): add Python version requirements and installation instructions

[adity1raut]

Fixed #19

1. Python Version Requirements Section

• Added explicit Python 3.13+ requirement explanation
• Included command to check current Python version
• Explained the dependency relationship with audioop-lts and discord.py voice features

2. Multi-Platform Installation Instructions

• macOS: Added Homebrew installation command for Python 3.13
• Ubuntu/Debian: Provided step-by-step instructions using deadsnakes PPA
• Windows: Referenced official Python.org download

3. Virtual Environment Setup

• Added proper virtual environment creation with Python 3.13
• Included activation commands for different operating systems
• Ensured dependency isolation and version compatibility

4. Alternative Installation Path

• Provided fallback installation method for users unable to upgrade Python
• Explained how to install discord.py without voice support
• Listed manual dependency installation as workaround
• Added clear warning about limited functionality without audioop-lts