So I made `brew changelog`. It parses the formula or cask, looks at the upstream repo, and tries to locate changelog-like files: CHANGELOG, NEWS, HISTORY, etc. Then it either prints the changelog to terminal or opens it in your browser.
brew tap pavel-voronin/changelog
brew changelog node -o
You can tweak behavior with options like --pattern, --print-url, or --allow-missing (try --help)
Feedback or contributions welcome!