This patch release improves the unicorn/filename-case rule to allow numbers
in all-caps markdown filenames.

Changes:
- Updated regex pattern from ^[A-Z][A-Z\-_]*\.md$ to ^[A-Z][A-Z0-9\-_]*\.md$
- Now supports filenames like MD5.md, SHA256.md, RFC2119.md
- Maintains backward compatibility with existing patterns (README.md, AGENT.md, etc.)