Add links to the version headings in the CHANGELOG.

CHANGELOG.md

@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Add links to the version headings in the CHANGELOG.
+
 ### Changed
 - Update `hnswlib` code to release [v0.5.2](https://github.com/nmslib/hnswlib/releases/tag/v0.5.2).
 - Use Go version `1.17`.
@@ -55,3 +58,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [0.1.0] - 2021-04-05
 ### Added
 - First release.
+
+[Unreleased]: https://github.com/SpecializedGeneralist/hnsw-grpc-server/compare/v1.0.0...HEAD
+[1.0.0]: https://github.com/SpecializedGeneralist/hnsw-grpc-server/compare/v0.2.0...v1.0.0
+[0.2.0]: https://github.com/SpecializedGeneralist/hnsw-grpc-server/compare/v0.1.1...v0.2.0
+[0.1.1]: https://github.com/SpecializedGeneralist/hnsw-grpc-server/compare/v0.1.0...v0.1.1
+[0.1.0]: https://github.com/SpecializedGeneralist/hnsw-grpc-server/releases/tag/v0.1.0