Updating changelog for release 2.0.0

Author: olivhoenen

docs/source/changelog.rst

@@ -3,8 +3,28 @@
 Changelog
 =========
 
+What's new in IMAS-Python 2.0.0
+-------------------------------
+
+Breaking change
+'''''''''''''''
+
+The package name was changed from `imaspy` to `imas` while porting the code to GitHub. This shall only affect the import statements in your code. 
+
+New features and improvements
+'''''''''''''''''''''''''''''
+
+- Add :py:func:`imas.util.to_xarray` to convert a full IDS or only specific paths herein to a Xarray ``Dataset``. See :ref:`Convert IMAS-Python IDSs directly to Xarray Datasets` for more details.
+- Implements automatic DD version conversion on :py:meth:`imas.db_entry.DBEntry.get` (conversion during :py:meth:`imas.db_entry.DBEntry.put` is not supported as this is rarely needed and easily worked around).
+- Enable lazy loading when reading data from a netCDF file.
+- Minor performance improvement loading data from a netCDF file.
+- Replace ``versioneer`` by ``setuptools-scm`` to determine the version of the code.
+- Use `saxonche <https://pypi.org/project/saxonche/>`__ instead of the JAR for XSL transforms (when building versions of the DD).
+- Updating the README, CONTRIBUTING guidelines and documentation after making the code open access.
+
+
 What's new in IMAS-Python 1.2.0
---------------------------
+-------------------------------
 
 New features and improvements
 '''''''''''''''''''''''''''''