Updated cmake minimum required to 3.5-4.0

Author: redboltz

CMakeLists.txt

@@ -1,12 +1,4 @@
-if(${CMAKE_VERSION} VERSION_GREATER "3.4")
-    CMAKE_MINIMUM_REQUIRED (VERSION 3.5)
-else()
-    CMAKE_MINIMUM_REQUIRED (VERSION 2.8.12)
-    IF ((CMAKE_VERSION VERSION_GREATER 3.1) OR
-        (CMAKE_VERSION VERSION_EQUAL 3.1))
-        CMAKE_POLICY(SET CMP0054 NEW)
-    ENDIF ()
-endif()
+CMAKE_MINIMUM_REQUIRED (VERSION 3.5...4.0)
 
 PROJECT (msgpack-cxx LANGUAGES CXX)