Added support for ``NO_COLOR`` and ``FORCE_COLOR`` environment variables to control colored output.

For more information, see `the docs <https://docs.pytest.org/en/stable/reference.html#environment-variables>`__.

Added support for :envvar:`NO_COLOR` and :envvar:`FORCE_COLOR` environment variables to control colored output.

Use sphinx references for NO_COLOR and FORCE_COLOR in changelog
Use sphinx references for NO_COLOR and FORCE_COLOR in changelog
