fix requests req, vcr fails + py3.4 support was dropped

requirements.txt

@@ -1,6 +1,6 @@
 six>=1.10.0
 pycryptodomex>=3.7.0
-requests>=2.9.1
+requests>=2.9.1,<2.22.0
 vdf>=2.0
 gevent>=1.2.0
 protobuf>=3.0.0

setup.py

@@ -17,7 +17,7 @@ with open(path.join(here, 'steam/__init__.py'), encoding='utf-8') as f:
 install_requires = [
     'six>=1.10',
     'pycryptodomex>=3.7.0',
-    'requests>=2.9.1',
+    'requests>=2.9.1,<2.22.0',
     'vdf>=2.0',
     'gevent>=1.2.0',
     'protobuf>=3.0.0',