JuMP v0.23.1

Diff since v0.23.0

Closed issues:

• Inconsistent Nonlinear Naming (#2892)
• Rational infinite constraints do not work anymore (#2894)

Merged pull requests:

• [docs] update roadmap for post v1.0 (#2883) (@odow)
• Deprecate nl_expr_string and nl_constraint_string (#2893) (@odow)
• Add complex and real affine expressions (#2895) (@blegat)
• Fix variable bounds passed as Rational{Int}(Inf) (#2896) (@odow)
• Fix printing of im coefficient (#2897) (@blegat)
• Fix conj and implement real/imag (#2899) (@blegat)
• Fix solution_summary with empty model (#2900) (@odow)
• Fix jump_function with Complex coefficients (#2901) (@blegat)
• Prep for v0.23.1 (#2902) (@odow)
• Fixes for arithmetic with complex quadratic (#2903) (@blegat)
• Add abs2 (#2904) (@blegat)
• Fix Complex support in quadratic constraints (#2905) (@blegat)