fix changelog links

Author: tot-ra

CHANGELOG.md

@@ -233,6 +233,7 @@ DELETE /schema/:schemaId
 - Examples of gateway + 2 federated services
 
 [unreleased]: https://github.com/pipedrive/graphql-schema-registry/compare/v3.0.1...HEAD
+[3.1.0]: https://github.com/pipedrive/graphql-schema-registry/compare/v3.0.1...v3.1.0
 [3.0.1]: https://github.com/pipedrive/graphql-schema-registry/compare/v3.0.0...v3.0.1
 [3.0.0]: https://github.com/pipedrive/graphql-schema-registry/compare/v2.2.4...v3.0.0
 [2.2.4]: https://github.com/pipedrive/graphql-schema-registry/compare/v2.2.3...v2.2.4