bumped minimum required CMake version to 3.5 [skip ci]

Author: firewave

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8.12)
+cmake_minimum_required(VERSION 3.5)
 project(Cppcheck)
 
 include(cmake/cxx11.cmake)

readme.md

@@ -44,6 +44,8 @@ There are multiple compilation choices:
 
 ### CMake
 
+The minimum required version is CMake 3.5.
+
 Example, compiling Cppcheck with cmake:
 
 ```shell

releasenotes.txt

@@ -30,4 +30,5 @@ Other:
   - You can suppress warnings in current file using "-file".
   - You can suppress all warnings where macro is used using "-macro"
 - fixed CMake build with UBSAN and GCC
-- The minimum required compiler versions have been bumped to GCC 5.1 / Clang 3.5
+- The minimum required compiler versions have been bumped to GCC 5.1 / Clang 3.5
+- The minimum required CMake version has been bumped to 3.5