Quick PR Description

Generate a concise PR description by analyzing the diff against a base branch.

Output the result in a markdown file named PR_DESCRIPTION.md.

Instructions

1. First, determine the base branch using the repository's default branch:

   Try these methods in order until one succeeds:

   Method 1 - GitHub CLI:

   BASE_BRANCH=$(gh repo view --json defaultBranchRef -q '.defaultBranchRef.name' 2>/dev/null)