Address han's review feedback: - Changed feat/feature-name to feat/issue-N-feature-name - Consistent with fix/issue-N-name format
- Add VERSIONING.md documenting 0.1.x/0.2.x branch strategy - Add docs/CHANGELOG.md with release notes for v0.1.0-v0.2.1 - Update CONTRIBUTING.md: fix master->main, add develop branch - Closes #120