Update paramiko version to fit python2/3 environment

Author: pureyxu

requirements.txt

@@ -3,7 +3,7 @@ six >= 1.10
 python_dateutil >= 2.5.3
 setuptools >= 21.0.0
 urllib3 >= 1.15.1
-paramiko >= 2.7.1
+paramiko == 2.7.1
 pyjwt >= 1.7.1
 requests >= 2.20.1
 typing>=3.7.4.1

setup.py

@@ -12,7 +12,7 @@
 VERSION = '1.8.0'
 
 REQUIRES = ['urllib3 >= 1.15', 'six >= 1.10', 'certifi >= 14.05.14',
-            'python-dateutil >= 2.5.3', 'paramiko >= 2.4.2',
+            'python-dateutil >= 2.5.3', 'paramiko == 2.7.1',
             'PyJWT >= 1.7.1', 'requests >= 2.20.1']
 
 readme = open('README.md', 'r')