Update documentation, versioning and changelog configuration

[RD2W]

This PR includes several improvements to the project configuration and documentation:

1. Updated README.md with proper YAML escaping for regex patterns in configuration examples
2. Enhanced versioning documentation with detailed information about build variables
3. Improved changelog grouping in goreleaser.yml with case-insensitive matching

These changes improve the developer experience by providing clearer documentation and more flexible changelog generation.