Bump requests-oauthlib from 1.3.1 to 1.4.0 (#691)

Bumps [requests-oauthlib](https://github.com/requests/requests-oauthlib) from 1.3.1 to 1.4.0.
- [Release notes](https://github.com/requests/requests-oauthlib/releases)
- [Changelog](https://github.com/requests/requests-oauthlib/blob/master/HISTORY.rst)
- [Commits](requests/requests-oauthlib@v1.3.1...v1.4.0)

---
updated-dependencies:
- dependency-name: requests-oauthlib
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]