Bump tensorflow from 1.15.4 to 2.9.3

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 1.15.4 to 2.9.3.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v1.15.4...v2.9.3)

---
updated-dependencies:
- dependency-name: tensorflow
  dependency-type: direct:production
...

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Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 h5py==2.8.0
 Keras==2.6.0rc3
-tensorflow==1.15.4
+tensorflow==2.9.3
 dlib==19.16.0
 opencv_python==3.4.3.18
 imutils==0.5.1