fix diff links in changelog
@@ -217,7 +217,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
- Began keeping record of changes in `changelog.md`
-[Unreleased]: https://github.com/pymedphys/pymedphys/compare/v0.8.4...master
+[Unreleased]: https://github.com/pymedphys/pymedphys/compare/v0.8.5...master
+[0.8.5]: https://github.com/pymedphys/pymedphys/compare/v0.8.4...v0.8.5
[0.8.4]: https://github.com/pymedphys/pymedphys/compare/v0.8.3...v0.8.4
[0.8.3]: https://github.com/pymedphys/pymedphys/compare/v0.8.2...v0.8.3
[0.8.2]: https://github.com/pymedphys/pymedphys/compare/v0.8.1...v0.8.2
