Conan 2: CMake output is not streamed

[markfinal]

You only get to see the output once it's finished.

[markfinal]

This is due to this in conans/util/runners.py because pipes are being used

        try:
            proc = subprocess.Popen(command, shell=shell, stdout=out, stderr=err, cwd=cwd)
        except Exception as e:
            raise ConanException("Error while running cmd\nError: %s" % (str(e)))

        proc_stdout, proc_stderr = proc.communicate()
        # If the output is piped, like user provided a StringIO or testing, the communicate
        # will capture and return something when thing finished