docu update.

CITATION

 If you use the Climate Data Operators (CDO) to process data for an article in a scientific publication, please cite:
 
-Schulzweida, Uwe. (2021, October 31). CDO User Guide (Version 2.0.0). Zenodo. http://doi.org/10.5281/zenodo.5614769
+Schulzweida, Uwe. (2022). CDO User Guide (2.1.0). Zenodo. https://doi.org/10.5281/zenodo.7112925
 
-@misc{schulzweida_uwe_2020_5614769,
+@misc{schulzweida_uwe_2022_7112925,
   author       = {Schulzweida, Uwe},
   title        = {CDO User Guide},
   month        = oct,
-  year         = 2021,
+  year         = 2022,
   publisher    = {Zenodo},
-  version      = {2.0.0},
-  doi          = {10.5281/zenodo.5614769},
-  url          = {https://doi.org/10.5281/zenodo.5614769}
-}
+  version      = {2.1.0},
+  doi          = {10.5281/zenodo.7112925},
+  url          = {https://doi.org/10.5281/zenodo.7112925}
+}
\ No newline at end of file

NEWS

@@ -29,6 +29,7 @@ Version 2.1.1 (10 December 2022):
 Version 2.1.0 (14 October 2022):
 
    New features:
+     * Option --chunksize: Set the chunk size of the horizonal grid
      * Option --nsb: Set number of significant bits, used for bit-rounding with NetCDF 4.9.0
      * Added support for NCZarr
      * zonmean: added support for data on unstructured grids