Bump tensorflow from 1.15.2 to 1.15.4 in /Deployment/rnn_app (tirthajyoti#12)

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 1.15.2 to 1.15.4.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v1.15.2...v1.15.4)

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

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

Author: dependabot[bot]

Deployment/rnn_app/requirements.txt

@@ -9,4 +9,4 @@ flask==1.0.3
 jinja2==2.10.1
 wtforms==2.2.1
 keras==2.2.4
-tensorflow==1.15.2
+tensorflow==1.15.4