Pin tensorflow-probability to a specific version.

This matches the documentation for specifying version for this project. Additionally, recent version of `tensorflow-probability` are releasing breaking changes and the existing version specifier allows these to breaking changes to be unintentionally pulled in.

PiperOrigin-RevId: 476443999

Author: michaelreneer

requirements.txt

@@ -32,5 +32,5 @@ scikit-learn>=1.0,==1.*
 scipy~=1.7
 tensorflow-datasets~=4.5
 tensorflow-estimator~=2.4
-tensorflow-probability~=0.15
+tensorflow-probability==0.15.0
 tensorflow~=2.4

setup.py

@@ -38,7 +38,7 @@
         'scipy~=1.7',
         'tensorflow-datasets~=4.5',
         'tensorflow-estimator~=2.4',
-        'tensorflow-probability~=0.15',
+        'tensorflow-probability==0.15.0',
         'tensorflow~=2.4',
     ],
     packages=find_packages())