Bump version number to 4.2.0.

Author: plusvic

setup.py

@@ -350,7 +350,7 @@ def run(self):
 
 setup(
     name='yara-python',
-    version='4.1.0',
+    version='4.2.0',
     description='Python interface for YARA',
     long_description=readme,
     license='Apache 2.0',