Bump version to 1.5.4.

Lukasz Kaiser · Ryan Sepassi · commit 11f65763f785 · 2018-03-02T13:01:07.000-08:00
PiperOrigin-RevId: 187657679
diff --git a/setup.py b/setup.py
@@ -5,7 +5,7 @@
 
 setup(
     name='tensor2tensor',
-    version='1.5.3',
+    version='1.5.4',
     description='Tensor2Tensor',
     author='Google Inc.',
     author_email='no-reply@google.com',
