Update requests to 2.28.1

[pyup-bot]

This PR updates requests from 2.27.1 to 2.28.1.

Changelog

2.28.1

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

**Improvements**

- Speed optimization in `iter_content` with transition to `yield from`. (6170)

**Dependencies**

- Added support for chardet 5.0.0 (6179)
- Added support for charset-normalizer 2.1.0 (6169)

2.28.0

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

**Deprecations**

- ⚠️ Requests has officially dropped support for Python 2.7. ⚠️ (6091)
- Requests has officially dropped support for Python 3.6 (including pypy3.6). (6091)

**Improvements**

- Wrap JSON parsing issues in Request's JSONDecodeError for payloads without
an encoding to make `json()` API consistent. (6097)
- Parse header components consistently, raising an InvalidHeader error in
all invalid cases. (6154)
- Added provisional 3.11 support with current beta build. (6155)
- Requests got a makeover and we decided to paint it black. (6095)

**Bugfixes**

- Fixed bug where setting `CURL_CA_BUNDLE` to an empty string would disable
cert verification. All Requests 2.x versions before 2.28.0 are affected. (6074)
- Fixed urllib3 exception leak, wrapping `urllib3.exceptions.SSLError` with
`requests.exceptions.SSLError` for `content` and `iter_content`. (6057)
- Fixed issue where invalid Windows registry entires caused proxy resolution
to raise an exception rather than ignoring the entry. (6149)
- Fixed issue where entire payload could be included in the error message for
JSONDecodeError. (6036)

Links

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