message: Also adding a note about Cuda supported version
diff: ## Deprecations
  +* TensorFlow 1.7 may be the last time we support Cuda versions below 8.0.
  + Starting with TensorFlow 1.8 release, 8.0 will be the minimum supported
  + version.
  * TensorFlow 1.7 may be the last time we support cuDNN versions below 6.0.
  Starting with TensorFlow 1.8 release, 6.0 will be the minimum supported
  version.
  