Rename DataUpdateCurrentsPerPhase to DataUpdateCurrentPerPhase (BC)

[andig]

Fix #182

[andig]

@sthelen-enqs this is a breaking chore fix that would help improve naming consistency

[uhl]

@andig Thanks for the contribution— you're right that CurrentPerPhase is the correct name and Currents is the outlier (the MPC interface method is already CurrentPerPhase).
I'd hold off on merging this as a hard rename though. DataUpdateCurrentsPerPhase is part of the public API and I can see at least a handful of downstream consumers on GitHub. A cosmetic rename that forces every one of them to touch their import sites on the next release feels like a poor tradeoff for the ergonomic win — especially since the CONTRIBUTING guideline explicitly discourages purely cosmetic patches, and there's no changelog convention here to loudly signal the break.
What do you think?

[andig]

@uhl thank you for the comment. I agree this is a breaking change. However- with 0.x versions breaking changes are to be expected. The issue here is that it makes the library usage confusing and imho more than a cosmetic rename. PR (and commit) is already named BC to signal that.