Consistent output type from `pesummary.utils.credible_interval.credible_interval`
The purpose of this MR is to make the output type from pesummary.utils.credible_interval.credible_interval
consistent when weights is provided or not. This fixed #312 (closed). cc @matthew-pitkin as this may impact cwinpy/cwinpy!170 (merged).
Edited by Charlie Hoy