Remove duplicate entries (#1391)

Author: Klaus Zimmermann

doc/changelog.rst

@@ -43,18 +43,16 @@ Deprecations
 Documentation
 ~~~~~~~~~~~~~
 
--  Set version to 2.3.0 (`#1162 <https://github.com/ESMValGroup/ESMValCore/pull/1162>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
--  Final changelog for 2.3.0 (`#1163 <https://github.com/ESMValGroup/ESMValCore/pull/1163>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
 -  Add link to plot directory in index.html (`#1256 <https://github.com/ESMValGroup/ESMValCore/pull/1256>`__) `Stef Smeets <https://github.com/stefsmeets>`__
 -  Work around issue with yapf not following PEP8 (`#1277 <https://github.com/ESMValGroup/ESMValCore/pull/1277>`__) `Bouwe Andela <https://github.com/bouweandela>`__
 -  Update the core development team (`#1278 <https://github.com/ESMValGroup/ESMValCore/pull/1278>`__) `Bouwe Andela <https://github.com/bouweandela>`__
 -  Update the documentation of the provenance interface (`#1305 <https://github.com/ESMValGroup/ESMValCore/pull/1305>`__) `Bouwe Andela <https://github.com/bouweandela>`__
 -  Update version number to first release candidate 2.4.0rc1 (`#1363 <https://github.com/ESMValGroup/ESMValCore/pull/1363>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
--  Update changelog for 2.4.0 (`#1366 <https://github.com/ESMValGroup/ESMValCore/pull/1366>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
 -  Update to new ESMValTool logo (`#1374 <https://github.com/ESMValGroup/ESMValCore/pull/1374>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
 -  Update version number for third release candidate 2.4.0rc3 (`#1384 <https://github.com/ESMValGroup/ESMValCore/pull/1384>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
 -  Update changelog for 2.4.0rc3 (`#1385 <https://github.com/ESMValGroup/ESMValCore/pull/1385>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
 -  Update version number to final 2.4.0 release (`#1389 <https://github.com/ESMValGroup/ESMValCore/pull/1389>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
+-  Update changelog for 2.4.0 (`#1366 <https://github.com/ESMValGroup/ESMValCore/pull/1366>`__) `Klaus Zimmermann <https://github.com/zklaus>`__
 
 Fixes for datasets
 ~~~~~~~~~~~~~~~~~~