fix: Homebrew tap workflow — remove heredoc causing YAML parse error

[pbertsch]

The Python heredoc (<<PYEOF) inside a YAML run: block caused a workflow file parse error on GitHub Actions.

Rewrote the homebrew job to:

• Clone the tap repo directly using the PAT for auth
• Use sed for version update (single-line replacement)
• Use awk for SHA256 updates (find URL line, update next line)
• Commit and push directly — no GitHub API content endpoint needed