[Bug]: Outdated CMake Version in CONTRIBUTING.md

[Sickeroni]

Describe the issue

Link
There is following information:

Python v3.6 or newer (for running some of the tests and re-generating certain source files from templates)
CMake v2.8.12 or newer

But the command target_compile_features(${name} PUBLIC cxx_std_14) is used in /googletest/cmake/internal_utils.cmake
This feature was introduced in Version 3.1 of CMake. Link

The main CMakeLists.txt also sets a minimum of 3.13.

Steps to reproduce the problem

read the files

What version of GoogleTest are you using?

irrelevant

What operating system and version are you using?

irrelevant

What compiler and version are you using?

irrelevant

What build system are you using?

irrelevant

Additional context

I would have updated it, but not sure if there are features using more modern versions of cmake.
If wanted, i can update it to 3.13 (or other if stated)