Update changelog

Author: robertodr

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Change Log
 
-## [Unreleased]
+## [Version 2.0.0] - 2020-04-14
 
 ### Changed
 
@@ -96,7 +96,8 @@ modernize the library. See the [migration guide](https://xcfun.readthedocs.io/en
 - **BREAKING** The Fortran interface is no longer build with the code, but
   shipped as a separate file to be compiled within your own Fortran code.
 
-[Unreleased]: https://github.com/dftlibs/xcfun/compare/v2.0.0a7...HEAD
+[Unreleased]: https://github.com/dftlibs/xcfun/compare/v2.0.0...HEAD
+[Version 2.0.0]: https://github.com/dftlibs/xcfun/compare/v2.0.0a7...v2.0.0
 [Version 2.0.0a7]: https://github.com/dftlibs/xcfun/compare/v2.0.0a6...v2.0.0a7
 [Version 2.0.0a6]: https://github.com/dftlibs/xcfun/compare/v2.0.0a5...v2.0.0a6
 [Version 2.0.0a5]: https://github.com/dftlibs/xcfun/compare/v2.0.0a4...v2.0.0a5