i think you'll want:

[repl.repl.py]
ipython = True

because adding options after a goal name is the same as prefixing them with that name -- so your command could have also been written as

./pants --repl-repl-py-ipython repl src/starsky_utils

. it is however strange that setting

--repl-py-ipython

without the deeper scope doesn't work, and it's not clear to me why we have a nested

[repl.repl.py]

scope at all