Update requirements

requirements-frozen.txt

+certifi==2018.10.15
+chardet==3.0.4
+Click==7.0
+idna==2.7
+requests==2.20.0
+urllib3==1.24

requirements.txt

-requests>=2.16.0
+requests
+click

setup.py

@@ -14,9 +14,9 @@ setup(
     package_data={
         '': ['*.md', 'LICENSE', 'README'],
     },
-    install_requires=read_requirements('requirements.txt'),
+    install_requires=read_requirements('requirements-frozen.txt'),
     extras_require={
-        'test': read_requirements('tests-requirements.txt'),
+        'test': read_requirements('requirements-tests.txt'),
     },
     license='MIT',
     description="API client for the Arkindex project",