Update README.md

Author: cordmaur

README.md

@@ -18,7 +18,7 @@ All the details and tests has been described in the article <b>Automatic Water D
 Cordeiro, M. C. R.; Martinez, J.-M.; Peña-Luque, S. Automatic Water Detection from Multidimensional Hierarchical Clustering for Sentinel-2 Images and a Comparison with Level 2A Processors. Remote Sensing of Environment 2021, 253, 112209. https://doi.org/10.1016/j.rse.2020.112209.
 
 ## Changelog
-### Release 1.5.6 
+### Release 1.5.7 
 - new entry point runWaterDetect.py 
 - Namespace correction for different versions of sklearn package 
 - New treatment for negative reflectance values (individual pixel correction)