Bug due to mismatch with dual sign convention

[blegat]

In this line:

DiffOpt.jl/src/diff_opt.jl

Line 702 in 6a74501

dQ * z + dq + dG' * λ + dA' * ν

This should be - dA' * ν even if it is + dA' * ν because ν is the MOI dual which is the opposite as the dual used in the paper.
We should probably reverse ν when we get the dual so that we don't have these complications.
This sign was correctly reversed here:

DiffOpt.jl/src/diff_opt.jl

Lines 467 to 472 in 6a74501

	# this is the previously implemented
	return dν[i] * z[j] - ν[i] * dz[j]
	# from the paper, teh correct solution should be this
	# and thec correct fix is probably correcting the signs of the duals
	# since MOI standard is different from text book shadow prices
	# return dν[i] * z[j] + ν[i] * dz[j]