Bump version to 2.3.1

Update furo to 2024.08.06

Update index.rst

Bump certifi version in docs build

Appease dependabot

CI fix: ensure a numpy <2 wheel is available

Rename line optimization input data columns (#138)

Rename fixCost, operatingCost, edgeSource, edgeTarget to camel case

Enforce gencost.n <= 3 for OPF input data (#114)

* Update NY case file (limit to quadratic gencost functions)

* Be stricter with gencost functions (enforce gencost.n <= 3)

* Update gencost docs warning

* Correct genpower -> gencost

Fixes for scipy sparse handling (#106)

Fall back to spmatrix classes for gurobipy.
Use scipy.sparse.issparse instead of type checks.

Require gurobipy>=10.0.1

Format python files

New version of black gets a bit more opinionated about empty lines