fix RequestsDependencyWarning by updating requests

it fixes the
python2.7/site-packages/requests/__init__.py:91: RequestsDependencyWarning: urllib3 (1.25.1) or chardet (3.0.4) doesn't match a supported version! RequestsDependencyWarning) by upgrading requests from 2.21.0 to 2.22.0. This implies in fact the urllib3 upgrade from (1.25.1 -> 1.25.3) which resolves the warning. ref. streamlink/streamlink#2448 (comment)

Author: damdo

requirements.txt

@@ -1,4 +1,3 @@
-
 asn1crypto==0.24.0
 certifi==2019.3.9
 cffi==1.12.3
@@ -14,9 +13,9 @@ pyasn1==0.4.5
 pycparser==2.19
 PyNaCl==1.3.0
 pyOpenSSL==19.0.0
-requests==2.21.0
+requests==2.22.0
 six==1.12.0
-urllib3==1.25.1
+urllib3==1.25.3
 aiohttp==3.5.4; python_version >= '3.5'
 async-timeout==3.0.1; python_version >= '3.5'
 attrs==19.1.0; python_version >= '3.5'