Bug fix

Bug fix in applying the crossover operation when the `crossover_probability` parameter is used. 
Thanks to Eng. Hamada Kassem, RA/TA, Construction Engineering and Management, Faculty of Engineering, Alexandria University, Egypt: https://www.linkedin.com/in/hamadakassem

Author: ahmedfgad

docs/source/conf.py

@@ -22,7 +22,7 @@
 author = 'Ahmed Fawzy Gad'
 
 # The full version, including alpha/beta/rc tags
-release = '2.8.0'
+release = '2.8.1'
 
 master_doc = 'index'