message: relax cudnn version requirement
diff: @@ -232,9 +232,9 @@ function(detect_cuDNN)
  message(STATUS "Found cuDNN: ver. ${CUDNN_VERSION} found (include: ${CUDNN_INCLUDE}, library: ${CUDNN_LIBRARY})")
  - string(COMPARE LESS "${CUDNN_VERSION_MAJOR}" 8 cuDNNVersionIncompatible)
  + string(COMPARE LESS "${CUDNN_VERSION_MAJOR}" 7 cuDNNVersionIncompatible)
  if(cuDNNVersionIncompatible)
  - message(FATAL_ERROR "cuDNN version >=8 is required.")
  + message(FATAL_ERROR "cuDNN version >=7 is required.")
  endif()
  set(CUDNN_VERSION "${CUDNN_VERSION}" PARENT_SCOPE)
  