updates library version

Author: sufyankhanrao

setup.py

@@ -12,7 +12,7 @@
 
 setup(
     name='apimatic-core',
-    version='0.2.20',
+    version='0.2.21',
     description='A library that contains core logic and utilities for '
                 'consuming REST APIs using Python SDKs generated by APIMatic.',
     long_description=long_description,