Release 6.1 - FEAT: Adding the Code Churn metric and improving its computation by up to 50x in `PyDriller/repositories_picker.py`

New Features

Code Churn Metric: Introduced a new metric to measure code churn, providing deeper insights into code stability and changes over time.
Repositories Picker: Added a new Makefile rule for selecting repositories to analyze code metrics.
Code Metrics Analyzer: Enhanced Makefile rule to analyze metrics against repository attributes.
Metrics Changes Analyzer: New Makefile rule for tracking changes in metrics across repositories.
Full Path Handling: Implemented full path management for repositories' PDF and JSON files.
Thread Support: Improved repository setup and filtering functions with multi-threading for better performance.

Performance Boost: Enhanced computation for the Code Churn metric by up to 50 times, increasing the efficiency of metric extraction and analysis.
Output Enhancements: Updated output formatting for better readability and clarity in various scripts.
Repository Attributes Updates: Refined methods for updating and handling repository attributes, ensuring accuracy and consistency.

Cleaned up code by removing redundant function calls and optimizing output handling.
Standardized naming conventions and organization of constants and functions across scripts.
Enhanced documentation throughout the codebase, improving maintainability and understanding of functionality.

Resolved issues related to file path conversions and key name discrepancies in metric tracking.
Corrected verbose output positioning and ensured accurate path constants for repositories.

Updated comments and docstrings to reflect recent changes and improve clarity for future development.

Full Changelog: v6.0...v6.1