Bump tensorflow from 1.15.2 to 2.5.0

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 1.15.2 to 2.5.0.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v1.15.2...v2.5.0)

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

Author: dependabot[bot]

requirements.txt

@@ -10,7 +10,7 @@ numpy
 pebble
 pickle-mixin
 pycrypto
-tensorflow==1.15.2
+tensorflow==2.5.0
 tensorflow_hub==0.4.0
 timeloop
 zipfile36

setup.py

@@ -48,7 +48,7 @@
     install_requires=[
         'argparse', 'grpcio', 'grpcio-tools', 'libeospy', 'loguru',
         'matplotlib', 'miniupnpc', 'networkx', 'numpy', 'pebble',
-        'pickle-mixin', 'pycrypto', 'sklearn', 'tensorflow==1.15.2',
+        'pickle-mixin', 'pycrypto', 'sklearn', 'tensorflow==2.5.0',
         'tensorflow_hub==0.4.0', 'timeloop', 'zipfile36'
     ],  # Optional
 )