If true, targets built in the Python 2 configuration will appear under an
output root that includes the suffix '-py2', while targets built for Python
3 will appear in a root with no Python-related suffix. This means that the
`bazel-bin` convenience symlink will point to Python 3 targets rather than
Python 2. If you enable this option it is also recommended to enable `--
incompatible_py3_is_default`.