Fix pandas FutureWarning

[twrightsman]

This patch should fix the following warnings I was getting; output is the same:

compleasm.py:1544: FutureWarning: When grouping with a length-1 list-like, you will need to pass a length-1 tuple to get_group in 
a future version of pandas. Pass `(name,)` instead of `name` to silence this warning.