Bump tensorflow from 2.0.3 to 2.4.0

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.0.3 to 2.4.0.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.0.3...v2.4.0)

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

Author: dependabot[bot]

requirements.txt

@@ -7,4 +7,4 @@ sklearn
 tqdm==4.28.1
 matplotlib==2.2.3
 pyaudio==0.2.11
-tensorflow==2.0.3
+tensorflow==2.4.0