Bump tensorflow from 1.0.0 to 1.15.2 in /training-lstm

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 1.0.0 to 1.15.2.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v1.0.0...v1.15.2)

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

Author: dependabot[bot]

training-lstm/requirements.txt

@@ -1,3 +1,3 @@
 numpy==1.10.4
 scipy==0.17.0
-tensorflow==1.0.0
+tensorflow==1.15.2