Upgrade default TF cuda version to cuda 10.

PiperOrigin-RevId: 227180147
diff --git a/configure.py b/configure.py
index c588381..bb59063 100644
--- a/configure.py
+++ b/configure.py
@@ -33,7 +33,7 @@
   from distutils.spawn import find_executable as which
 # pylint: enable=g-import-not-at-top
 
-_DEFAULT_CUDA_VERSION = '9.0'
+_DEFAULT_CUDA_VERSION = '10.0'
 _DEFAULT_CUDNN_VERSION = '7'
 _DEFAULT_CUDA_COMPUTE_CAPABILITIES = '3.5,7.0'
 _DEFAULT_CUDA_PATH = '/usr/local/cuda'