[CUDA][docs] explicitly require CUDA 9.0 or higher (#3885)

CMakeLists.txt

@@ -153,7 +153,7 @@ if(__INTEGRATE_OPENCL)
 endif(__INTEGRATE_OPENCL)
 
 if(USE_CUDA)
-    find_package(CUDA REQUIRED)
+    find_package(CUDA 9.0 REQUIRED)
     include_directories(${CUDA_INCLUDE_DIRS})
     LIST(APPEND CMAKE_CUDA_FLAGS -Xcompiler=${OpenMP_CXX_FLAGS} -Xcompiler=-fPIC -Xcompiler=-Wall)
 
@@ -161,8 +161,8 @@ if(USE_CUDA)
     if(CUDA_VERSION VERSION_GREATER_EQUAL "10.0")
         list(APPEND CUDA_ARCHS "7.5")
     endif()
-    list(POP_BACK CUDA_ARCHS CUDA_LAST_SUPORTED_VERSION)
-    list(APPEND CUDA_ARCHS "${CUDA_LAST_SUPORTED_VERSION}+PTX")
+    list(POP_BACK CUDA_ARCHS CUDA_LAST_SUPPORTED_ARCH)
+    list(APPEND CUDA_ARCHS "${CUDA_LAST_SUPPORTED_ARCH}+PTX")
     CUDA_SELECT_NVCC_ARCH_FLAGS(CUDA_ARCH_FLAGS ${CUDA_ARCHS})
 
     LIST(APPEND CMAKE_CUDA_FLAGS ${CUDA_ARCH_FLAGS})

docs/Installation-Guide.rst

@@ -594,7 +594,7 @@ On Linux a CUDA version of LightGBM can be built using **CUDA**, **CMake** and *
 
 The following dependencies should be installed before compilation:
 
--  **CUDA** libraries. Please refer to `this detailed guide`_.
+-  **CUDA** 9.0 or later libraries. Please refer to `this detailed guide`_.
 
 -  **CMake** 3.16 or later.
 

python-package/README.rst

@@ -119,7 +119,7 @@ Build CUDA Version
 
 All requirements from `Build from Sources section <#build-from-sources>`__ apply for this installation option as well, and `CMake`_ (version 3.16 or higher) is strongly required.
 
-**CUDA** library is needed: details for installation can be found in `Installation Guide <https://github.com/microsoft/LightGBM/blob/master/docs/Installation-Guide.rst#build-cuda-version-experimental>`__.
+**CUDA** library (version 9.0 or higher) is needed: details for installation can be found in `Installation Guide <https://github.com/microsoft/LightGBM/blob/master/docs/Installation-Guide.rst#build-cuda-version-experimental>`__.
 
 Build HDFS Version
 ~~~~~~~~~~~~~~~~~~