Update CMakeLists.txt
Update the CMAKE minimum version from `3` to `3.0` to fix error in Windows 10 x64 with CMAKE 3.15.4:
cmake_minimum_required could not parse VERSION "3".
# License: MIT #
# #
###################################################################################
-cmake_minimum_required(VERSION 3 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
project(unity LANGUAGES C DESCRIPTION "C Unit testing framework.")
