Add links to history

Author: willingc

CHANGELOG.md

@@ -165,7 +165,8 @@ This release was tagged in git and GitHub but not released to PyPI.
 
 Initial release to PyPI.
 
-[Unreleased]: https://github.com/pyopensci/pyosmeta/compare/v0.1.5...HEAD
+[Unreleased]: https://github.com/pyopensci/pyosmeta/compare/v0.1.6...HEAD
+[v1.6]: https://github.com/pyopensci/pyosmeta/compare/v0.1.5...v0.1.6
 [v0.2.4]: https://github.com/pyopensci/pyosmeta/compare/v0.2.3...v0.2.4
 [v0.2.3]: https://github.com/pyopensci/pyosmeta/compare/v0.15...v0.2.3
 [v0.2.2]: https://github.com/pyopensci/pyosmeta/compare/v0.15...v0.2.2