Update README.md

update version number

Author: gabrielaznar

README.md

@@ -8,7 +8,7 @@ Authors: David N. Bresch <[email protected]>, Gabriela Aznar Siguan <aznarsig@ethz
 
 Date: 2018-11-06
 
-Version: 0.2.1
+Version: 1.2.3
 
 See [documentation](http://climada-python.readthedocs.io/en/latest/) and [tutorial](https://github.com/davidnbresch/climada_python/tree/master/script/tutorial/1_main_climada.ipynb).