Log Message:
py-requests: updated to 2.19.1

2.19.1:
Bugfixes
- Fixed issue where status_codes.py's init function failed trying to append to
  a __doc__ value of None.

2.19.0:
Improvements
- Warn user about possible slowdown when using cryptography version < 1.3.4
- Check for invalid host in proxy URL, before forwarding request to adapter.
- Fragments are now properly maintained across redirects. (RFC7231 7.1.2)
- Removed use of cgi module to expedite library load time.
- Added support for SHA-256 and SHA-512 digest auth algorithms.
- Minor performance improvement to Request.content.
- Migrate to using collections.abc for 3.7 compatibility.

Bugfixes
- Parsing empty Link headers with parse_header_links() no longer return one \ 
bogus entry.
- Fixed issue where loading the default certificate bundle from a zip archive
  would raise an IOError.
- Fixed issue with unexpected ImportError on windows system which do not support \ 
winreg module.
- DNS resolution in proxy bypass no longer includes the username and password in
  the request. This also fixes the issue of DNS queries failing on macOS.
- Properly normalize adapter prefixes for url comparison.
- Passing None as a file pointer to the files param no longer raises an exception.
- Calling copy on a RequestsCookieJar will now preserve the cookie policy correctly.