v0.15.1 release planning

[kandersolar]

This release slipped my mind until @cwhanse mentioned it.

I think we should prioritize getting this one merged, as it is time-sensitive:

• Migrate NREL references to NLR (National Laboratory of the Rockies) #2705

These ones seem close, just need some reviews:

• Remove pandas series usage from ephemeris #2626
• calculate surface angles using unit normal #2702

Please comment with any additions.

[cwhanse]

• Adds faiman_rad and ross models to get_cell_temperature(). #2631

[RDaxini]

Suggestion:

• Update contributing guidelines #2726

[kandersolar]

• iotools test failures with pandas 3 #2728

[cwhanse]

#2723 or no? Or, hold for 0.15.2?

I agree a better long-term path is to add a real-only option to scipy, but that's not pending, and would also require advancing pvlib's scipy to scipy's latest.

If #2723 is not merged, the loss is limited to slower performance with scipy's current lambertw.