DOC: Update DOI badge to point to all versions [skip ci]

Author: effigies

README.rst

@@ -34,8 +34,9 @@ NIPYPE: Neuroimaging in Python: Pipelines and Interfaces
     :target: http://gitter.im/nipy/nipype
     :alt: Chat
 
-.. image:: https://zenodo.org/badge/DOI/10.5281/zenodo.581704.svg
-   :target: https://doi.org/10.5281/zenodo.581704
+.. image:: https://zenodo.org/badge/DOI/10.5281/zenodo.596855.svg
+   :target: https://doi.org/10.5281/zenodo.596855
+   :alt: Citable DOI
 
 Current neuroimaging software offer users an incredible opportunity to
 analyze data using a variety of different algorithms. However, this has