Update requests to 2.25.0

[pyup-bot]

This PR updates requests from 2.22.0 to 2.25.0.

Changelog

2.25.0

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

**Improvements**

- Added support for NETRC environment variable. (5643)

**Dependencies**

- Requests now supports urllib3 v1.26.

**Deprecations**

- Requests v2.25.x will be the last release series with support for Python 3.5.
- The `requests[security]` extra is officially deprecated and will be removed
in Requests v2.26.0.

2.24.0

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

**Improvements**

- pyOpenSSL TLS implementation is now only used if Python
either doesn't have an `ssl` module or doesn't support
SNI. Previously pyOpenSSL was unconditionally used if available.
This applies even if pyOpenSSL is installed via the
`requests[security]` extra (5443)

- Redirect resolution should now only occur when
`allow_redirects` is True. (5492)

- No longer perform unnecessary Content-Length calculation for
requests that won't use it. (5496)

2.23.0

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

**Improvements**

- Remove defunct reference to `prefetch` in Session `__attrs__` (5110)

**Bugfixes**

- Requests no longer outputs password in basic auth usage warning. (5099)

**Dependencies**

- Pinning for `chardet` and `idna` now uses major version instead of minor.
This hopefully reduces the need for releases everytime a dependency is updated.

Links

• PyPI: https://pypi.org/project/requests
• Changelog: https://pyup.io/changelogs/requests/
• Docs: https://requests.readthedocs.io

[pyup-bot]

Closing this in favor of #393