deps: update dependency requests to v2.28.1 (#237)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [requests](https://requests.readthedocs.io) ([source](https://github.com/psf/requests), [changelog](https://github.com/psf/requests/blob/master/HISTORY.md)) | `==2.27.1` -> `==2.28.1` | [![age](https://badges.renovateapi.com/packages/pypi/requests/2.28.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/pypi/requests/2.28.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/pypi/requests/2.28.1/compatibility-slim/2.27.1)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/pypi/requests/2.28.1/confidence-slim/2.27.1)](https://docs.renovatebot.com/merge-confidence/) |

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