Update minimum Python version and dependencies

* Update supported Python versions
* Update dependencies to be in alignment
* Remove explicit dependency on requests library as it is a transitive dependency of ibm-cloud-sdk-core

Author: rtveitch

requirements.txt

@@ -1,2 +1 @@
-requests==2.21.0
 ibm-cloud-sdk-core>=0.4.2,<=0.5.0

setup.py

@@ -1,23 +1,12 @@
 #!/usr/bin/env python
 import os
 import re
-import sys
 
 from setuptools import setup, find_packages
-# IbmCos Config sdk python version check
-_valid = sys.version_info[:2] == (2, 7) or sys.version_info >= (3,4)
-if not _valid:
-    sys.exit("Sorry, IBM COS Config SDK only supports versions 2.7, 3.4, 3.5, 3.6, 3.7 of python.")
-
 
 ROOT = os.path.dirname(__file__)
 VERSION_RE = re.compile(r'''__version__ = ['"]([a-z0-9._-]+)['"]''')
 
-requirements = [
-    'requests',
-    'ibm-cloud-sdk-core>=0.4.2,<=0.5.0',
-]
-
 
 def get_version():
     '''
@@ -39,19 +28,21 @@ def get_version():
     scripts=[],
     packages=find_packages(exclude=['tests*']),
     include_package_data=True,
-    install_requires=requirements,
+    python_requires='~=3.5',
+    install_requires=[
+        'ibm-cloud-sdk-core>=0.4.2,<=0.5.0',
+    ],
     license="Apache License 2.0",
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Intended Audience :: Developers',
         'Natural Language :: English',
         'License :: OSI Approved :: Apache Software License',
         'Programming Language :: Python',
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
     ],
 )