Bump tensorflow from 2.3.1 to 2.5.1

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.3.1 to 2.5.1.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.3.1...v2.5.1)

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

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

Author: dependabot[bot]

requirements.txt

@@ -21,7 +21,7 @@ scipy==1.4.1
 sklearn==0.0
 tables==3.6.1
 tensorboard==2.3.0
-tensorflow==2.3.1
+tensorflow==2.5.1
 tensorflow-estimator==2.3.0
 tifffile==2020.7.4
 torch==1.8.0+cu111