Bump s3transfer from 0.14.0 to 0.15.0

Bumps [s3transfer](https://github.com/boto/s3transfer) from 0.14.0 to 0.15.0.
- [Changelog](https://github.com/boto/s3transfer/blob/develop/CHANGELOG.rst)
- [Commits](boto/s3transfer@0.14.0...0.15.0)

---
updated-dependencies:
- dependency-name: s3transfer
  dependency-version: 0.15.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -54,7 +54,7 @@ sqlparse==0.5.0
 gunicorn==23.0.0
 
 # boto3 deps
-s3transfer==0.14.0
+s3transfer==0.15.0
 jmespath==1.0.0
 
 botocore>=1.15.0,<1.42.0