Fix spin

[caleb-johnson]

Dice expects an integer spin value in [-1, 4]. The solve_hci argument, spin_sq does not reflect this in its description nor type hint. The input to solve_hci and solve_fermion should be an argument called int: spin, which is passed directly to Dice. We will match Dice's default of -1 and write an appropriate description.

We should also provide the user with the expval of S^2 in both functions using the outputs from Dice.

• Deprecate and ignore spin_sq argument in solve_hci
• Create spin argument in both functions and use it as input to Dice
• Update description of spin to match behavior in Dice
• Write release note
• Provide E(S^2) as outputs from both functions (See Spin sq #58)