[BUILD] Update DEFAULT_CUDA_VERSION and DEFAULT_CUDNN_VERSION in configure.py.

Signed-off-by: Tongxuan Liu <tongxuan.ltx@alibaba-inc.com>

Author: liutongxuan

configure.py

@@ -33,8 +33,8 @@
   from distutils.spawn import find_executable as which
 # pylint: enable=g-import-not-at-top
 
-_DEFAULT_CUDA_VERSION = '10'
-_DEFAULT_CUDNN_VERSION = '7'
+_DEFAULT_CUDA_VERSION = '11'
+_DEFAULT_CUDNN_VERSION = '8'
 _DEFAULT_TENSORRT_VERSION = '5'
 _DEFAULT_CUDA_COMPUTE_CAPABILITIES = '6.0,6.1,7.0,7.5,8.0'