Suppress CMake policy warning (CMP0048)

[mbrobbel]

As suggested in #2150.

This moves the cmake_policy command before the project definition, where it used to be until: 67265e0. It was introduced with #782.

This suppresses the following policy warning:

CMake Warning (dev) at CMakeLists.txt:6 (project):
  Policy CMP0048 is not set: project() command manages VERSION variables.
  Run "cmake --help-policy CMP0048" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  The following variable(s) would be set to empty:

    CMAKE_PROJECT_VERSION
    CMAKE_PROJECT_VERSION_MAJOR
    CMAKE_PROJECT_VERSION_MINOR
    CMAKE_PROJECT_VERSION_PATCH
This warning is for project developers.  Use -Wno-dev to suppress it.

[gennadiycivil]

@mbrobbel thank you for this. Just to note CMake support is community-based. The maintainers do not use CMake internally.
With that, what is the before/after effect this would create and how is this beneficial? Basically if you could provide before and after logs to show the difference.

[mbrobbel]

Building this project with CMake before the patch:

CMake Warning (dev) at CMakeLists.txt:6 (project):
  Policy CMP0048 is not set: project() command manages VERSION variables.
  Run "cmake --help-policy CMP0048" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  The following variable(s) would be set to empty:

    CMAKE_PROJECT_VERSION
    CMAKE_PROJECT_VERSION_MAJOR
    CMAKE_PROJECT_VERSION_MINOR
    CMAKE_PROJECT_VERSION_PATCH
This warning is for project developers.  Use -Wno-dev to suppress it.

-- Configuring done
-- Generating done
-- Build files have been written to: /code/googletest/build

After applying this patch the warning is suppressed:

-- Configuring done
-- Generating done
-- Build files have been written to: /code/googletest/build

It was reported first in #709, and fixed with #782. 67265e0 resulted in the warning showing again, because, as mentioned in #2150 the cmake_policy command should come before the project command.