GitLab

Bumps [tensorflow-gpu](https://github.com/tensorflow/tensorflow) from 1.14.0 to 1.15.2.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](https://github.com/tensorflow/tensorflow/compare/v1.14.0...v1.15.2

)
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: Shaden Smith <ShadenTSmith@gmail.com>
Co-authored-by: Jeff Rasley <jerasley@microsoft.com>

* Enables NCCL backend in @distributed_test

* Adds pytest-forked to avoid CUDA re-initialization issue.

* paste typo

* transcription typo

* Adding testing documentation to README.md

* Add pytest to requirements.txt