Bump requests from 2.22.0 to 2.25.1 in /tests (#47)

Bumps [requests](https://github.com/psf/requests) from 2.22.0 to 2.25.1.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/master/HISTORY.md)
- [Commits](psf/requests@v2.22.0...v2.25.1)

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

tests/requirements.txt

@@ -1,3 +1,3 @@
-requests==2.22.0
+requests==2.25.1
 boto3==1.11.6
 pytest==4.4.1