Bump tensorflow from 1.15.0 to 1.15.2

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 1.15.0 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@v1.15.0...v1.15.2)

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

Author: dependabot[bot]

requirements.txt

@@ -4,7 +4,7 @@ tinydb==3.9.0.post1
 youtube_dl
 spacy==2.1.3
 pyowm==2.9.0
-tensorflow==1.15.0
+tensorflow==1.15.2
 deepspeech==0.9.0a3
 requests>=2.20.0
 nltk