Bump tensorflow-gpu from 1.15 to 1.15.2

Bumps [tensorflow-gpu](/~https://github.com/tensorflow-gpu/tensorflow-gpu) from 1.15 to 1.15.2.
- [Release notes](/~https://github.com/tensorflow-gpu/tensorflow-gpu/releases)
- [Commits](/~https://github.com/tensorflow-gpu/tensorflow-gpu/commits)

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

requirements.txt

@@ -7,4 +7,4 @@ sentencepiece
 tensorflow-text==1.15.0rc0
 tensor2tensor==1.15.0
 tfds-nightly
-tensorflow-gpu==1.15
+tensorflow-gpu==1.15.2

setup.py

@@ -43,10 +43,10 @@
         'tensorflow-text==1.15.0rc0',
         'tfds-nightly',
         'tensor2tensor==1.15.0',
-        'tensorflow-gpu==1.15',
+        'tensorflow-gpu==1.15.2',
     ],
     extras_require={
-        'tensorflow': ['tensorflow-gpu==1.15'],
+        'tensorflow': ['tensorflow-gpu==1.15.2'],
     },
     classifiers=[
         'Development Status :: 4 - Beta',