Newer CMake is going to drop <2.8.12

So update to 2.8.12.2 (in Ubuntu 14.04)

CentOS 7 has a way to install CMake3.

This avoids the warning in newer CMakes:

flatcc/CMakeLists.txt:5 (cmake_minimum_required):
  Compatibility with CMake < 2.8.12 will be removed from a future version of
  CMake.

Author: powderluv

CMakeLists.txt

@@ -1,8 +1,8 @@
 # Ubuntu 14.04 (Trusty)
-#cmake_minimum_required (VERSION 2.8.12.2)
+cmake_minimum_required (VERSION 2.8.12.2)
 # Centos 7
 #cmake_minimum_required (VERSION 2.8.11)
-cmake_minimum_required (VERSION 2.8)
+#cmake_minimum_required (VERSION 2.8)
 
 # Experimental for generating compile_commands.json so editors with
 # clangd language server support can use it. Symlink