Update requests to 2.25.0

[pyup-bot]

This PR updates requests from 2.24.0 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.

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 #46