Update requests to 2.19.1

[pyup-bot]

This PR updates requests from 2.14.2 to 2.19.1.

Changelog

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.

**Dependencies**

-   We now support idna v2.7.
-   We now support urllib3 v1.23.

2.18.4

-------------------

**Improvements**

-   Error messages for invalid headers now include the header name for
 easier debugging

**Dependencies**

-   We now support idna v2.6.

2.18.3

-------------------

**Improvements**

-   Running `$ python -m requests.help` now includes the installed
 version of idna.

**Bugfixes**

-   Fixed issue where Requests would raise `ConnectionError` instead of
 `SSLError` when encountering SSL problems when using urllib3 v1.22.

2.18.2

-------------------

**Bugfixes**

-   `requests.help` no longer fails on Python 2.6 due to the absence of
 `ssl.OPENSSL_VERSION_NUMBER`.

**Dependencies**

-   We now support urllib3 v1.22.

2.18.1

-------------------

**Bugfixes**

-   Fix an error in the packaging whereby the `*.whl` contained
 incorrect data that regressed the fix in v2.17.3.

2.18.0

-------------------

**Improvements**

-   `Response` is now a context manager, so can be used directly in a
 `with` statement without first having to be wrapped by
 `contextlib.closing()`.

**Bugfixes**

-   Resolve installation failure if multiprocessing is not available
-   Resolve tests crash if multiprocessing is not able to determine the
 number of CPU cores
-   Resolve error swallowing in utils set\_environ generator

2.17.3

-------------------

**Improvements**

-   Improved `packages` namespace identity support, for monkeypatching
 libraries.

2.17.2

-------------------

**Improvements**

-   Improved `packages` namespace identity support, for monkeypatching
 libraries.

2.17.1

-------------------

**Improvements**

-   Improved `packages` namespace identity support, for monkeypatching
 libraries.

2.17.0

-------------------

**Improvements**

-   Removal of the 301 redirect cache. This improves thread-safety.

2.16.5

-------------------

-   Improvements to `$ python -m requests.help`.

2.16.4

-------------------

-   Introduction of the `$ python -m requests.help` command, for
 debugging with maintainers!

2.16.3

-------------------

-   Further restored the `requests.packages` namespace for compatibility
 reasons.

2.16.2

-------------------

-   Further restored the `requests.packages` namespace for compatibility
 reasons.

No code modification (noted below) should be necessary any longer.

2.16.1

-------------------

-   Restored the `requests.packages` namespace for compatibility
 reasons.
-   Bugfix for `urllib3` version parsing.

**Note**: code that was written to import against the
`requests.packages` namespace previously will have to import code that
rests at this module-level now.

For example:

 from requests.packages.urllib3.poolmanager import PoolManager

Will need to be re-written to be:

 from requests.packages import urllib3
 urllib3.poolmanager.PoolManager

Or, even better:

 from urllib3.poolmanager import PoolManager

2.16.0

-------------------

-   Unvendor ALL the things!

2.15.1

-------------------

-   Everyone makes mistakes.

2.15.0

-------------------

**Improvements**

-   Introduction of the `Response.next` property, for getting the next
 `PreparedResponse` from a redirect chain (when
 `allow_redirects=False`).
-   Internal refactoring of `__version__` module.

**Bugfixes**

-   Restored once-optional parameter for
 `requests.utils.get_environ_proxies()`.

Links

• PyPI: https://pypi.org/project/requests
• Changelog: https://pyup.io/changelogs/requests/
• Homepage: http://python-requests.org

[coveralls]

Coverage remained the same at ?% when pulling 6e379d1 on pyup-update-requests-2.14.2-to-2.19.1 into 3fed9dc on master.